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Let $X$ be a vector space, equipped with two norms $\|\cdot\|_1$ and $\|\cdot\|_2$ Which are equivalent. What is the easiest way to prove that these two equivalent norms induce same topology? | Note that (1) all norms on finite dimensional vector space are equivalent. And here (2) norms on vector space are equivalent iff they have same topology. Question : How can we prove (2) ? Please recommend reference Thank you in anticipation | I am trying to get an intuitive idea of how the affects Quantum computation. My understanding is that given a qubit $Q$ in superposition $Q_0 \left| 0 \right> + Q_1 \left| 1 \right>$, NCT states another Qubit $S$ cannot be designed such that $S$ is equivalent to the state of $Q$. Now the catch is, what does Eq... | eng_Latn | 4,000 |
Could there be 3 particles (instead of only 2 particles) that could be connected by same quantum entanglement (like minus, plus and "some third position")? | So I know that two particles can be entangled in a quantum way, but is it possible that more than two particles be entangled in a quantum way? Most descriptions provide with two-particles cases, so I wonder. (It's hard to think of three particles entangled in spin, or so.) | Im trying to run the following code \documentclass[border=10pt]{standalone} \usepackage{pgfplots} \pgfplotsset{width = 7cm, compat = 1.8} \begin{document} \begin{tikzpicture} \begin{axis}[domain = -2:2, domain y = 0:2*pi] \addplot3[contour gnuplot = {output point meta = rawz, number=10, labels=false}, samples = 41, z ... | eng_Latn | 4,001 |
How can i reach the treasure in the right door of Desert Temple? I can't jump there. | It's big and empty and I can't get up to the top, what should I do? I can't jump high enough, anti-gravity doesn't seem to do anything either. My first tactic was to use the octopus summoning crown to create a pile of octopi that I could climb up, but when I teleported to the back of the room they followed me back, tr... | When constructing the matrices for the two CNOT based on the target and control qubit, I can use reasoning: "If $q_0$==$|0\rangle$, everything simply passes through", resulting in an Identity matrix style $\begin{bmatrix}1&0\\0&1\end{bmatrix}$ in the top left. "If $q_0==|1\rangle$, we need to let $q_0$ pass an... | eng_Latn | 4,002 |
Quantization of energy A mirror reflects all electromagnetic waves that fall on it in the visible spectrum. How does the mechanism of reflection work? Is it because when a photon hits an electron, the electron jumps to a higher energy level and then to come back to its initial energy level, it emits a photon. If the e... | Explain reflection laws at the atomic level The "equal angles" law of refection on a flat mirror is a macroscopic phenomenon. To put it in anthropomorphic terms, how do individual photons know the orientation of the mirror so as to bounce off in the correct direction? | How do we perform transverse measurements in a two level system? In quantum mechanics any two level system can be mapped onto effective spin variables. If the system is defined by two energy levels, $|E_1\rangle$ and $|E_2\rangle$, the Hamiltonian is $$ H = \left(\begin{array}{cc} E_1 & 0 \\ 0 & E_2 \end{array... | eng_Latn | 4,003 |
How are quantum gates implemented in reality? Quantum gates seem to be like black boxes. Although we know what kind of operation they will perform, we don't know if it's actually possible to implement in reality (or, do we?). In classical computers, we use AND, NOT, OR, XOR, NAND, NOR, etc which are mostly implemented ... | How are quantum gates realised, in terms of the dynamic? When expressing computations in terms of a quantum circuit, one makes use of gates, that is, (typically) unitary evolutions. In some sense, these are rather mysterious objects, in that they perform "magic" discrete operations on the states. They are essentially ... | How do I apply differential cryptanalysis to a block cipher? I have read a lot of summaries of block ciphers particularly with regards to the NIST competitions stating that reduced-round block ciphers are – for example – vulnerable to differential cryptanalysis. I have a general idea that the application of differenti... | eng_Latn | 4,004 |
Confused about the application of Hadamard gate to uncorrelated qubits Why does applying the following circuit on a $00$ state produce $|0\rangle \otimes |+\rangle = \frac{1}{\sqrt{2}}(|00\rangle + |01\rangle)$. Shouldn't it produce $ |+\rangle \otimes |0\rangle = \frac{1}{\sqrt{2}}(|00\rangle + |10\rangle)$? | Big Endian vs. Little Endian in Qiskit I've noticed that Q# favors Little Endian. Meaning that most operations are designed for this type of encoding. Is is it the same with Qiskit? | Deriving a QM expectation value for a square of momentum $\langle p^2 \rangle$ I already derived a QM expectation value for ordinary momentum which is: $$ \langle p \rangle= \int\limits_{-\infty}^{\infty} \overline{\Psi} \left(- i\hbar\frac{d}{dx}\right) \Psi \, d x $$ And I can read clearly that operator for momentu... | eng_Latn | 4,005 |
Anyone who has studied quantum mechanics know the following relation: $ 2 \otimes 2 = 3 \oplus 1 $ But how did a man woke up and said "Hell yeah, I'll use tensor product of two spin $1/2$ to simulate the interaction of two particles with spin $1/2$" ? Why didn't he start with the direct sum ? (And then, group theory ... | My text introduces multi-quibt quantum states with the example of a state that can be "factored" into two (non-entangled) substates. It then goes on to suggest that it should be obvious1 that the joint state of two (non-entangled) substates should be the tensor product of the substates: that is, for example, ... | It is well know that $SO(n)$ is connected and $O(n)$ has two connected components: $O^+(n)=\{A\in O(n):\det A=+1\}$ and $O^-(n)=\{A\in O(n):\det A=-1\}$. In what book can I find this property? | eng_Latn | 4,006 |
Is this possible to build a quantum network? Since quantum entangled particles can transfer the data of their spin properties faster than the speed of light and without any problem of weak signal, can we use quantum entanglement to transfer phone calls and internet connection? Why are we not building up a telecommunica... | Quantum entanglement faster than speed of light? recently i was watching a on quantum computing where the narrators describes that quantum entanglement information travels faster than light! Is it really possible for anything to move faster than light? Or are the narrators just wrong? Regards, | Shannon confusion and diffusion concept I read the document(not the whole document) from Shannon where he speaks about the concepts of confusion and diffusion. I read in many places(not in the document but around the internet) that confusion is enforced using substitution. Diffusion is enforced using permutation/transp... | eng_Latn | 4,007 |
Bands disappear after Raster Calculation ArcGIS I have a tif file containing 36 bands. After I applied raster calculation on the file the bands aggregate into one single band which I don't want because I need them for further calculation. People say that I can apply raster calculation on each band. I can do that but it... | How to prevent RGB composite flatten to 1 band after raster calculation I have a series of landsat wanting to process in raster calculator, but after doing the tool it happened these output images only contain one single band. They used to be RGB 3-band images. It is on arcmap 10.3. I was using raster calculator to re... | How to find the reduced density matrix of a four-qubit system? I have the state vector $|p\rangle$ made up of 4 qubits. Say system A is made up of the first and second qubits while system B is made up of qubits 3 and 4. I want to find the reduced density matrix of system A. I know I could separately extract qubits 1,... | eng_Latn | 4,008 |
Method to derive Matrix description of a circuit | How to interpret a quantum circuit as a matrix? | Direct proof that nilpotent matrix has zero trace | eng_Latn | 4,009 |
How do calculate ? | Is my expansion of the state $| x \rangle$ correct? | What are the answers for these basic quetions? | eng_Latn | 4,010 |
Source code for Hamiltonian measurement in qiskit | How to measure a qubit Hamiltonian in qiskit | Proving a graph has no Hamiltonian cycle | eng_Latn | 4,011 |
What's the point of hyperbolic trigonometric functions? I'm currently learning about hyperbolic trig functions, and i don't really get the point. At first, I found it really weird that the input is the area divided by 2, and just wondered what was the point of it anyways? So, are there any real world applications for ... | Real world uses of hyperbolic trigonometric functions I covered hyperbolic trigonometric functions in a recent maths course. However I was never presented with any reasons as to why (or even if) they are useful. Is there any good examples of their uses outside academia? | How do we perform transverse measurements in a two level system? In quantum mechanics any two level system can be mapped onto effective spin variables. If the system is defined by two energy levels, $|E_1\rangle$ and $|E_2\rangle$, the Hamiltonian is $$ H = \left(\begin{array}{cc} E_1 & 0 \\ 0 & E_2 \end{array... | eng_Latn | 4,012 |
Are sufficiently large key sizes enough to deter quantum attacks for symmetric key ciphers such as AES? | We know speedup brute-force attacks two times faster in block ciphers (e.g brute-forcing 128-bit keys take $2^{64}$ operations, not $2^{128}$). That explains why we are using 256-bit keys to encrypt top secrets. But on AES shows brute-forcing AES-256 take $2^{100}$ operations. Does this attack work with Grover's sear... | Suppose I want a strong 20-bit blockcipher. In other words, I want a function that takes a key (suppose the key is 128 bits), and implements a permutation from 20 bits to 20 bits. The set of permutations should be close to a randomly-chosen subset of size $2^{128}$ of all $2^{20}!$ permutations on 20 bits. I don't w... | eng_Latn | 4,013 |
QThread: Call a signal in the right thread | QThread and QTimer | Qt signaling across threads, one is GUI thread? | eng_Latn | 4,014 |
help remembering book title - multiverses/bladerunner-ish future. "sphere of influence. 2150"? | Story on quantum indeterminacy: protagonist has to “quantum select” a portable computer’s state | A fiber bundle over Euclidean space is trivial. | eng_Latn | 4,015 |
Good explanation of the QQ-plot algorithm? Anyone know a good explanation of the QQ-plot algorithm? , p.2. has the only one I've found and it's a bit unclear to me (particularly the percentiles and quantiles). | Benefits of using QQ-plots over histograms In , Nick Cox wrote: Binning into classes is an ancient method. While histograms can be useful, modern statistical software makes it easy as well as advisable to fit distributions to the raw data. Binning just throws away detail that is crucial in determining which distrib... | What would be an informative introduction to quantum computing software? I am new to Stack Exchange and am working on a quantum learning platform for minority youth groups (LGBTQ, low-income, at risk, etc). In the question below they are looking for courses on the subject, which I am also interested in, and do plan on... | eng_Latn | 4,016 |
How to check if 2 qubits are entangled? I know that 2 qubits are entangled if it is impossible to represent their joint state as a tensor product. But when we are given a joint state, how can we tell if it is possible to represent it as a tensor product? For example, I am asked to tell if the qubits are entangled for e... | How do I show that a two-qubit state is an entangled state? The Bell state $|\Phi^{+}\rangle = \frac{1}{\sqrt{2}}(|00\rangle + |11\rangle )$ is an entangled state. But why is that the case? How do I mathematically prove that? | How can I create a new extensible symbol? Given an arbitrary thin vertical symbol, can I create a new math delimiter from it (and if so, how)? Edit: Ideally, I would like to be able to create an extensible symbol, either built out an existing normal symbol, or even made from scratch. Edit 2: I am pretty sure that wh... | eng_Latn | 4,017 |
Is quantization of energy a purely mathematical result or is there a fundamental reason behind it? I'm new to QM and have some confusions about QM. It seems to be that the quantization of energy is just some result from solving the equation, like the infinite square well problem, the quantum harmonic oscillator. I wond... | Reason for the discreteness arising in quantum mechanics? What is the most essential reason that actually leads to the quantization. I am reading the book on quantum mechanics by Griffiths. The quanta in the infinite potential well for e.g. arise due to the boundary conditions, and the quanta in harmonic oscillator ari... | How do we perform transverse measurements in a two level system? In quantum mechanics any two level system can be mapped onto effective spin variables. If the system is defined by two energy levels, $|E_1\rangle$ and $|E_2\rangle$, the Hamiltonian is $$ H = \left(\begin{array}{cc} E_1 & 0 \\ 0 & E_2 \end{array... | eng_Latn | 4,018 |
Are there sites that allow to learn about quantum computing? So, I wanted to learn about quantum computing. What should I learn and where do I start? | What would be an informative introduction to quantum computing software? I am new to Stack Exchange and am working on a quantum learning platform for minority youth groups (LGBTQ, low-income, at risk, etc). In the question below they are looking for courses on the subject, which I am also interested in, and do plan on... | What is the "continue" keyword and how does it work in Java? I saw this keyword for the first time and I was wondering if someone could explain to me what it does. What is the continue keyword? How does it work? When is it used? | eng_Latn | 4,019 |
Is the interference quantum mechanical superposition the same as entanglement? Are the interference of two wave functions an equivalent way of saying that they are entangled? | Can Quantum Entanglement and Quantum Superposition be considered the same phenomenon? Quantum entanglement is known to be the exchange of quantum information between two particles at a distance, while quantum superposition is known to be the uncertainty of a particle (or particles) being in several states at once (whic... | Can I use a one time pad key twice with random plaintext? I understand the basics of OTP: $|\text{key space}| = |\text{plaintext space}|$ implies perfect security, key reuse destroys this. Cryptanalysis on the $N$-Time Pad for $N > 1$ involves finding patterns in the ciphertext; this, however, all seems based on th... | eng_Latn | 4,020 |
In connection to question, I am wondering how to calculate value $\langle \psi|\phi \rangle$ for arbitrary quantum states $|\psi\rangle$ and $|\phi\rangle$. A swap test is able to return only $|\langle \psi|\phi \rangle|^2$ which means that sign of the product is forgotten in case the inner product is real. Moreover, ... | I've been searching for a quantum algorithm to compute the the inner product between two $n$-qubit quantum states, namely $\langle\phi|\psi\rangle$, which is in general a complex number. One can get $|\langle\phi|\psi\rangle|^2$ through thte SWAP test for multiple qubits, but this is not really the inner product as the... | Take a sponge ball and compress it. The net force acting on the body is zero and the body isn't displaced. So can we conclude that there is no work done on the ball? | eng_Latn | 4,021 |
Quantum Entanglement - How To Interpret I have thought about quantum entanglement for some time, and I still don't quite understand the reasoning behind the conclusion that entangled particles somehow can communicate their state to each other instantaneously, even though they are separated by a substantial distance (e.... | Does entanglement not immediately contradict the theory of special relativity? Does entanglement not immediately contradict the theory of special relativity? Why are people still so convinced nothing can travel faster than light when we are perfectly aware of something that does? | Elastic collision in two dimensions Suppose a particle with mass $m_1$ and speed $v_{1i}$ undergoes an elastic collision with stationary particle of mass $m_2$. After the collision, particle of mass $m_1$ moves with speed $v_{1f}$ in a direction of angle $\theta$ above the line it was moving previously. Particle with m... | eng_Latn | 4,022 |
The Bakery: Advanced Pagination | From The Bakery, there's a new tutorial looking to help make pagination (more than just the basic stuff) simple on your site. This tutorial will attempt to cover some advanced techniques of pagination. In large this will cover Ajax pagination. Hopefully we can also uncover some of the better practices and techniques ... | By Joe Bauman Deseret Morning News A University of Utah physicist and his team have made a breakthrough that could pave the way to quantum computing, in which computers can calculate many billions of times faster than they do now. | eng_Latn | 4,023 |
Transportation using disintegration Is it physically possible to have one device, that will scan one object atom by atom and record it to some computer file and then send it to some other machine that could use this blueprint to rebuild that object? What are limitations of this? | Quantum teleportation - the alternative to destroying atoms Can't you just disassemble, not destroy our atoms and transport them to another teleporter via networking or telecoms? This is my thinking of how to keep the same person, not an exact copy of him/her, alive when teleporting. Please answer to tell me if it's ... | How can I send same email multiple times in iOS? I wanted to send a single email to different users. I save an email to drafts and send the email to a user and it goes to the sent box instead of staying in the drafts box. Is there a way I can send an email repeatedly from the drafts box? | eng_Latn | 4,024 |
What is spooky about the entanglement? If it doesn't allow for transmitting of any information, what was/is "spooky" about it? Is there anything spooky about it at all in the end? | Why is quantum entanglement considered to be an active link between particles? From everything I've read about quantum mechanics and quantum entanglement phenomena, it's not obvious to me why quantum entanglement is considered to be an active link. That is, it's stated every time that measurement of one particle affect... | What is the "rootless" feature in El Capitan, really? I have just learned about the "Rootless" feature in El Capitan, and I am hearing things like "There is no root user", "Nothing can modify /System" and "The world will end because we can't get root". What is the "Rootless" feature of El Capitan at a technical level?... | eng_Latn | 4,025 |
Why is the fusion power on the Voyager not enough to keep the replicators in operation? | If replicators allowed humans to stop working, why were replicators shut down in the Voyager? | Proof that the Casimir invariant of a representation commutes with everything | eng_Latn | 4,026 |
Does the recent announcement of information transmission via entanglement really indicate superluminal information transfer? Given that various answers here at Physics assert that information isn't transferred (such as this ), and given recent , does this invalidate our understanding of what's happening? Is information... | Quantum teleportation and no-communication theorem According to the Wikipedia article for the : In very rough terms, the theorem describes a situation that is analogous to two people, each with a radio receiver, listening to a common radio station: it is impossible for one of the listeners to use their radio receiv... | Can a well-timed Twisted Image kill a player using Tree of Redemption? What happens if my opponent activates and I cast with the life-exchange ability on the stack? Looking at the comp rules, these seem most relevant: 701.8a A spell or ability may instruct players to exchange something (for example, life totals ... | eng_Latn | 4,027 |
A biclustering approach for crowd judgment analysis | Learning Whom to Trust with MACE | Time-bin entangled photons from a quantum dot | eng_Latn | 4,028 |
What is the application of quantum physics? | What are some applications of quantum physics? | What are some good projects that I can do if I know only Java? | eng_Latn | 4,029 |
What are quantum numbers and what do they mean? | What are quantum numbers? | How does QR code work? | eng_Latn | 4,030 |
Quantum Key Distribution (QKD) has been partly developed by the UK's National Physical Laboratory .
It delivers data using photons - the smallest possible packets of light .
QKD shares a key between two users that is made completely secure using quantum mechanics .
Secure system enables eavesdroppers to be detected and... | By . Ellie Zolfagharifard . A ‘quantum leap’ has been made in encryption technology that could help securely transfer sensitive data. The technology - known as Quantum Key Distribution (QKD) – delivers private data using the smallest possible packets of light. Data could include encrypted personal information, such as ... | The Seattle Seahawks have revealed that a good part of their defensive strategy at the Super Bowl came from the fact that they were able to decode Peyton Manning's hand signals on the field. Controversial corner back Richard Sherman said that he and his fellow defenders cracked the code that the Denver Broncos quarterb... | eng_Latn | 4,031 |
Physicists create new form of matter that may hold the key to developing quantum machines | Harvard physicists have created a new form of matter -- dubbed a time crystal -- which could offer important insights into the mysterious behavior of quantum systems.
Traditionally speaking, crystals -- like salt, sugar or even diamonds -- are simply periodic arrangements of atoms in a three-dimensional lattice.
Time c... | Product News
Quadtech – “Seven colour management breakthroughs”
QuadTech talked to the editorial team of NarrowWebTech explaining how label printers and converters could meet the requirements regarding colour management. In this respect Craig du Mez, brand manager at QuadTech, named seven colour management breakthrough... | eng_Latn | 4,032 |
Could quantum computers in the future access parallel realities? | In what ways could quantum computers access parallel realities in the future? | How can self-awareness theoretically affect an artificial intelligence in the real-world? | eng_Latn | 4,033 |
How far away is the Quantum Internet from becoming a reality? | Quantum Computation: How far away is the Quantum Internet from becoming a reality? | When will time travelling (or at least time shifted vision) finally be possible? | eng_Latn | 4,034 |
What should everybody know about quantum spin liquids? | What is a quantum spin liquid? | What are the details behind the creation of the loading "Q" animation? | eng_Latn | 4,035 |
What is the difference of logic in quantum theory? | In a famous paper of 1936 with Garrett Birkhoff, the first work ever to introduce quantum logics, von Neumann and Birkhoff first proved that quantum mechanics requires a propositional calculus substantially different from all classical logics and rigorously isolated a new algebraic structure for quantum logics. The con... | Compass-M1 transmits in 3 bands: E2, E5B, and E6. In each frequency band two coherent sub-signals have been detected with a phase shift of 90 degrees (in quadrature). These signal components are further referred to as "I" and "Q". The "I" components have shorter codes and are likely to be intended for the open service.... | eng_Latn | 4,036 |
What is one of the independent multiphase winding sets configured for? | Doubly fed electric motors have two independent multiphase winding sets, which contribute active (i.e., working) power to the energy conversion process, with at least one of the winding sets electronically controlled for variable speed operation. Two independent multiphase winding sets (i.e., dual armature) are the max... | The reason for this is that a quantum disjunction, unlike the case for classical disjunction, can be true even when both of the disjuncts are false and this is, in turn, attributable to the fact that it is frequently the case, in quantum mechanics, that a pair of alternatives are semantically determinate, while each of... | eng_Latn | 4,037 |
They're obviously not opposed to messing with other races but do they place limits on their interference and/or interactions? We have witnessed Q (John de Lancie) change or alter many things for his amusement, but he only goes so far and usually puts things back as they were when he gets bored or done with whatever he... | Are there any rulesets or laws for Q or Q continuum? Anything, that would prevent them from doing... anything? Or at least limit them from doing something really bad? In "" episode Q explains to that they can do, have, get, become anything they want or appear anywhere they want, with just a snap of fingers. If that i... | A scene I made is not rendering, at all. This grey screen stays the same and nothing changes. Here are my settings: [ | eng_Latn | 4,038 |
My understanding of quantum entanglement is that when you measure the state of an entangled particle, its counterpart will measure a correlated state, i.e. we know for sure that if for example Particle A is measured to be in state A, then particle B will definitely be measured to be in a correlated state B at the same ... | From everything I've read about quantum mechanics and quantum entanglement phenomena, it's not obvious to me why quantum entanglement is considered to be an active link. That is, it's stated every time that measurement of one particle affects the other. In my head, there is a less magic explanation: the entangling mea... | I want to make it so I always have 50 entities in an area. So when 1 dies/despawns/leaves the area I want it to detect that and summon in a new entity, and yes I do want them to die/despawn/leave the area so preventing those things is not an option. | eng_Latn | 4,039 |
If I throw only one photon at the slits in Young's double slit experiment, can I get the interface pattern? | If just a single photon hit a single slit interferometer, what would happen? Would you just see a dot on the screen, or would there be a diffraction pattern? Furthermore, if you had a double slit interferometer but also had which-path information would there still be a diffraction pattern even though there is no interf... | I understand that faster-than-light communication is impossible when making single measurements, because the outcome of each measurement is random. However, shouldn't measurement on one side collapse the wave function on the other side, such that interference effects would disappear? Making measurements on "bunches" of... | eng_Latn | 4,040 |
A single photon, passing through a beamsplitter (BS), ends up in the state $\frac{1}{\sqrt2}(a_1^\dagger + a_2^\dagger)\lvert\operatorname{vac}\rangle$, which is a coherent superposition of the two possible spatial modes. Let us consider its momentum. When the photon goes straight its momentum doesn't change. However,... | In many experiments in quantum mechanics, a single photon is sent to a mirror which it passes through or bounces off with 50% probability, then the same for some more similar mirrors, and at the end we get interference between the various paths. This is fairly easy to observe in the laboratory. The interference means ... | The entire site is blank right now. The header and footer are shown, but no questions. | eng_Latn | 4,041 |
In the , photons reach D0 and shows a pattern, before its quantum entangled counterparts reach one of D1, D2, D3, or D4. The pattern differs based on what happens at the beam splitters (BSa and BSb) and whether the which-path information is lost. What if, instead of installing beam splitters BSa and BSb, we install ei... | The assumptions are: Alice and Bob have perfectly synchronized clocks Alice and Bob have successfully exchanged a pair of entangled photons The idea is simply to have Alice and Bob perform the Quantum Eraser Experiment (doesn't need to be the delayed choice). Alice and Bob agree on a specific time when Bob's pho... | I think that is pretty good prima-facia evidence that is just facilitating the deposition of crap. | eng_Latn | 4,042 |
I saw that particles can be paired and that no matter the distance what one does so does the other. Now, can we put each particle into a magnetic field where we could manipulate the spin? If you make the particle spin up zero or down for one and the other field detects the spin change you could have an instant communic... | According to the special theory of relativity, distant simultaneity depends on the observer's reference frame. And, according to the quantum theory, in the case of two entangled particles, a measure on one of the particles simultaneously affects the second one. Under which reference frame is this simultaneous? | The new Top-Bar does not show reputation changes from Area 51. | eng_Latn | 4,043 |
I already know how the Sun uses quantum tunneling to create nuclear fusion, but can't apply it to enzymes. Also, since I'm only in eighth grade, please use relatively simple language. Thanks! | The hydrogen protons undergo quantum tunnelling in the the sun to fuse into helium, but are only able to do so as they are under immense heat and pressure and the protons and electrons get separated. But our digestive system also makes use of quantum tunnelling to quicken the digestive process, but how do the enzymes f... | I have heard a few times that one way of describing quantum computers is that they essentially use the computing power of their counterparts in alternate realities that they access through superposition. My first question is, of course, is this actually an accurate description of how quantum computers work, or just ... | eng_Latn | 4,044 |
Recent news from Yale... We can predict the quantum leap before the particle collapses its superposition. We can even change it to whichever position we like in real time. In layman terms, as I understand with my limited knowledge, Schrodinger's cat can be SAVED. But... Also to my limited knowledge, the core of how a ... | new finding by Minev et al. seems to suggest that transitions between atomic states are not instantaneous, but continuous processes wherein a superposition smoothly adjusts from favoring one state to another (if I understand it correctly). The authors also claim to be able to catch a system "mid-jump" and reverse it. P... | I have heard a few times that one way of describing quantum computers is that they essentially use the computing power of their counterparts in alternate realities that they access through superposition. My first question is, of course, is this actually an accurate description of how quantum computers work, or just ... | eng_Latn | 4,045 |
When we perform a double slit experiment we receive interference pattern. when we measure in a specific slit the exact location of the photon (or electron) the interference pattern disappears and we receive only 2 light spots with no interference pattern. Now let's assume that we perform the double slit experiment on ... | I understand that faster-than-light communication is impossible when making single measurements, because the outcome of each measurement is random. However, shouldn't measurement on one side collapse the wave function on the other side, such that interference effects would disappear? Making measurements on "bunches" of... | Take a sponge ball and compress it. The net force acting on the body is zero and the body isn't displaced. So can we conclude that there is no work done on the ball? | eng_Latn | 4,046 |
I read in a book that () 160 qubits (quantum bits) could hold $2^{160} \approx1.46\times 10^{48}$ bits while the qubits were involved in computation." How does this calculation come about? The context of the statement is that a caffine molecule would require $10^{48}$ bits to be represented by a classical comput... | I recently read this , which stated: For scientists trying to design a compound that will attach itself to, and modify, a target disease pathway, the critical first step is to determine the electronic structure of the molecule. But modeling the structure of a molecule of an everyday drug such as penicillin, w... | I recently read this , which stated: For scientists trying to design a compound that will attach itself to, and modify, a target disease pathway, the critical first step is to determine the electronic structure of the molecule. But modeling the structure of a molecule of an everyday drug such as penicillin, w... | eng_Latn | 4,047 |
After reading an article on Schrodinger's Cat, it seems that if we take the environment as an observer, that superposition cannot occur because all atomic and subatomic entities would be observed all the time. Thus, something like quantum entanglement cannot occur. So if superposition cannot occur, why is superposition... | I don't understand how quantum mechanics (and therefore also quantum computers) can work given that while we work with quantum states, particles that this quantum state consist of cannot be observed, which is the most fundamental requirement. If I am not mistaken, by "observed" we mean interaction with any other part... | I think that is pretty good prima-facia evidence that is just facilitating the deposition of crap. | eng_Latn | 4,048 |
The trick of quantum computing is to take the advantage of wave mechanics (superposition) and entanglement. This allows to perform parallel computations/manipulations with $2^n$ superposed waves for $n$ bits. This principle does not rely on quantum mechanics. Superposed waves do also exist in classical mechanics (altho... | The intuition I have for why quantum computing can perform better than classical computing is that the wavelike nature of wavefunctions allow you to interfere multiple states of information with a single operation, which theoretically could allow for exponential speedup. But if it really is just constructive interfer... | I was wondering if quantum particles do actually exists in two different states simultaneously and if it has been proven they do indeed exists in a superposition of states. How has it been figured out since observing it would collapse the wave-function into one single state (two superposition of states into one ) as ... | eng_Latn | 4,049 |
I am starting to step into the field of Topological Quantum Information and Computation and am in search of tools which I can use to directly simulate or realize these transformations in a textual or graphical manner. | Does something like exist for topological (eg. braided) circuits? Alternatively, any ideas on how @ is getting (or something similar)? | The new Top-Bar does not show reputation changes from Area 51. | eng_Latn | 4,050 |
In chapter 1 of Quantum Computation and Quantum Information by Michael A. Nielsen & Isaac L. Chuang, I came across this paragraph on quantum teleportation, Intuitively, things look pretty bad for Alice. She doesn’t know the state $\lvert\psi\rangle$ of the qubit she has to send to Bob, and the laws of quantum mech... | I have two question concerning information content of qubit. Question 1: How many classical bits are needed to represent a qubit: A qubit can be represented by a vector $q = \begin{pmatrix}\alpha \\\beta \end{pmatrix}, ~~ \alpha, \beta \in \mathbb{C}$. So, we need four real numbers to represent it. But when facts tha... | Take a sponge ball and compress it. The net force acting on the body is zero and the body isn't displaced. So can we conclude that there is no work done on the ball? | eng_Latn | 4,051 |
How can quantum disjuction be illustrated? | The reason for this is that a quantum disjunction, unlike the case for classical disjunction, can be true even when both of the disjuncts are false and this is, in turn, attributable to the fact that it is frequently the case, in quantum mechanics, that a pair of alternatives are semantically determinate, while each of... | Compass-M1 transmits in 3 bands: E2, E5B, and E6. In each frequency band two coherent sub-signals have been detected with a phase shift of 90 degrees (in quadrature). These signal components are further referred to as "I" and "Q". The "I" components have shorter codes and are likely to be intended for the open service.... | eng_Latn | 4,052 |
Mathematically what is the difference between pure separable state and entangled state ? Can anyone explain with equations? | I am currently trying to establish a clear picture of pure/mixed/entangled/separable/superposed states. In the following I will always assume a basis of $|1\rangle$ and $|0\rangle$ for my quantum systems. This is what I have so far: superposed: A superposition of two states which a system $A$ can occupy, so $\frac{1}... | I am currently trying to establish a clear picture of pure/mixed/entangled/separable/superposed states. In the following I will always assume a basis of $|1\rangle$ and $|0\rangle$ for my quantum systems. This is what I have so far: superposed: A superposition of two states which a system $A$ can occupy, so $\frac{1}... | eng_Latn | 4,053 |
I'm not an expert and I don't know if already exists something like the following model, but I wrote a simple (mental) model to understand the basic concepts of quantum mechanics. I want to know if this model is valid or not. Red-or-Black (RoB) Card Model Suppose to have two cards, one is red and the other is blac... | Consider that we have two balls, one white and one black, and two distant observers A and B with closed eyes. We give the first ball to the observer A and the second ball to the observer B. The observers don't know the exact color (state) of their balls, they know only the probability of having one or another color, un... | The new Top-Bar does not show reputation changes from Area 51. | eng_Latn | 4,054 |
Please post further comments or answers to The probability that an initial quantum state $|\psi_i\rangle$ evolves to become the final quantum state $|\psi_f\rangle$ is given by \begin{eqnarray} P_{i \rightarrow f} &=& |\langle\psi_f|U_{i \rightarrow f}|\psi_i\rangle|^2 \tag{1}\\ &=& \langle\psi_f|U_{... | The probability that an initial quantum state $|\psi_i\rangle$ becomes the final quantum state $|\psi_f\rangle$ is given by \begin{eqnarray} P(i \rightarrow f) &=& |\langle\psi_f|\psi_i\rangle|^2 \tag{1}\\ &=& \langle\psi_f|\psi_i\rangle^*\langle\psi_f|\psi_i\rangle \\ &=& \langle\psi_i|\psi_f\... | The new Top-Bar does not show reputation changes from Area 51. | eng_Latn | 4,055 |
When was Leibniz an active philosopher? | German philosophers have helped shape western philosophy from as early as the Middle Ages (Albertus Magnus). Later, Leibniz (17th century) and most importantly Kant played central roles in the history of philosophy. Kantianism inspired the work of Schopenhauer and Nietzsche as well as German idealism defended by Fichte... | In a famous paper of 1936 with Garrett Birkhoff, the first work ever to introduce quantum logics, von Neumann and Birkhoff first proved that quantum mechanics requires a propositional calculus substantially different from all classical logics and rigorously isolated a new algebraic structure for quantum logics. The con... | eng_Latn | 4,056 |
Identifying a story about a boy who travels to a mirrored universe with ketchup that makes you intoxicated There was a novel I read back in the day about a boy who travels back and forth between a mirror-image of our universe. I am afraid I cannot recall much about the plot, except that mirrored food is inedible and w... | ID a book about a mirror world and 4th dimension I read a book about 10-15 years ago about a boy and a girl who find a mirror. What made the mirror special was, they were able to enter the reflection and be a part of the reverse image world. They end up going to school and when asked to write something on the board, it... | Understanding quantum entanglement.. help me validate this analogy! I'm struggling to understand the concept of quantum entanglement. I've distilled my understanding into an analogy, and I need your help to validate it. Here it is: Let's say I receive two envelopes. Both envelopes have this written on them: Hello!... | eng_Latn | 4,057 |
How does cold fusion work? I understand that in regular fusion, you use high levels of heat to accelerate atoms to speeds high enough to overcome nuclear force. What method would be used to achieve ? | Why is cold fusion considered bogus? Cold fusion is being mentioned a lot lately because of some new setup that apparently works. This is an unverified claim. See for example: ( of that last link in the Wayback Machine, given frequent from that page.) While we should give the scientific community time to ev... | What does a "real" quantum computer need for cryptanalysis and/or cryptographic attack purposes? The cryptographic world has been buzzing the word "quantum" for a while now (even the NSA is currently preparing itself for a post-quantum crypto world) and quantum-related hardware engineering is evolving constantly. For e... | eng_Latn | 4,058 |
Meaning of principal components I have difficulty understanding the meaning of the Principal Components (PC) - On one hand, PC are computed by finding loading vectors that maximize the variance, but on the other hand I read another interpretation that says PC are the closes to the n-observations. It seems to me like... | Principal component analysis "backwards": how much variance of the data is explained by a given linear combination of the variables? I have carried out a principal components analysis of six variables $A$, $B$, $C$, $D$, $E$ and $F$. If I understand correctly, unrotated PC1 tells me what linear combination of these var... | How are qubits better than classical bit if they collapse to a classical state after measurement? Classical computers store information in bits, which can either be $0$ or $1$, but, in a quantum computer, the qubit can store $0$, $1$ or a state that is the superposition of these two states. Now, when we make a "measure... | eng_Latn | 4,059 |
If we can predict the quantum leap, won't that render quantum computers useless? Recent news from Yale... We can predict the quantum leap before the particle collapses its superposition. We can even change it to whichever position we like in real time. In layman terms, as I understand with my limited knowledge, Schrodi... | Does the new finding on "reversing a quantum jump mid-flight" rule out any interpretations of QM? new finding by Minev et al. seems to suggest that transitions between atomic states are not instantaneous, but continuous processes wherein a superposition smoothly adjusts from favoring one state to another (if I understa... | Tsunami dampening mechanisms Encouraged by the zeitgeist let me ask the following: Is it feasible (now or in the future) to build systems a certain distance of a vulnerable coastline which can serve to dampen a tsunami before it reaches the coast itself? The following picture comes to mind. We have some device which ... | eng_Latn | 4,060 |
What's stopping two independent observers from measuring the speed and position at the same time, separately? From This means, it doesn't take into account, the Uncertainty Principle of Quantum Mechanics, which says that an object can not have both a well defined position, and a well defined speed: the more ac... | Uncertainty principle and multiple observers My understanding is that an observer can measure the precise location of a particle so long as the corresponding uncertainty in momentum measurement is not an issue and vice-versa. Say there is such an observer, interested in the precise position of a particular particle.... | How are qubits better than classical bit if they collapse to a classical state after measurement? Classical computers store information in bits, which can either be $0$ or $1$, but, in a quantum computer, the qubit can store $0$, $1$ or a state that is the superposition of these two states. Now, when we make a "measure... | eng_Latn | 4,061 |
Atoms: boson or fermion? The spin of fundamental particles determines if they are bosons or fermions. The atoms also have bosonic or fermionic behavior, for example $\require{mhchem}\ce{^4He}$ has bosonic and $\ce{^3He}$ has fermionic statistics. Which quantity of atom determines its statistics? | Huge confusion with Fermions and Bosons and how they relate to total spin of atom I am supremely confused when something has spin or when it does not. For example, atomic Hydrogen has 4 fermions, three quarks to make a proton, and 1 electron. There is an even number of fermions, and each fermion has a 1/2 spin. Since t... | How are qubits better than classical bit if they collapse to a classical state after measurement? Classical computers store information in bits, which can either be $0$ or $1$, but, in a quantum computer, the qubit can store $0$, $1$ or a state that is the superposition of these two states. Now, when we make a "measure... | eng_Latn | 4,062 |
How does an outcome of photon measurement 1 affect Photon 2 in quantum entanglement? I know I am missing something and this question is probably very silly, but I would like to understand. Quoting an article: If one photon is measured to be in a +1 state, the other must be in a -1 state. Since the outcome of one ... | Understanding quantum entanglement.. help me validate this analogy! I'm struggling to understand the concept of quantum entanglement. I've distilled my understanding into an analogy, and I need your help to validate it. Here it is: Let's say I receive two envelopes. Both envelopes have this written on them: Hello!... | Why can we apply the $E=hf$ equation for electrons? So in my textbook, it states that the $E=hf$ equation applies to electrons, and all particles, not just photons. But in order to prove this, wouldn't these particles need to have zero mass, to satisfy $E=pc$ from Einstein's equation? In Einstein's theory of relativ... | eng_Latn | 4,063 |
Choosing a book to gain general knowledge about biology I will be first year undergraduate at Physics department next year and last year I was at the Medicine faculty. I want do double major in the second year of faculty with Molecular Biology and Genetics. The intersection of biology and physics is my interest. I have... | Introductory biology text for an outsider I'm a maths major and I have an interest in learning biology. I know very, very little; I know how babies are made and that's about it. Could anyone recommend a stimulating text to read for its own sake and also to use to learn biology? | Understanding quantum entanglement.. help me validate this analogy! I'm struggling to understand the concept of quantum entanglement. I've distilled my understanding into an analogy, and I need your help to validate it. Here it is: Let's say I receive two envelopes. Both envelopes have this written on them: Hello!... | eng_Latn | 4,064 |
I got "BEGIN PGP PUBLIC KEY BLOCK" attached to an email and I don't know what it is Okay, I have no clue what this is, but I just received an email that has this in it. -----BEGIN PGP PUBLIC KEY BLOCK----- [redacted] -----END PGP PUBLIC KEY BLOCK----- If this means something, could someone decode it for me? If n... | what is PGP public key block? There's PGP public key block posted on some websites (eg. ). It's not hex code. it uses much more alphabet characters. What is it? Why is this information posted? how can i use it? | Understanding quantum entanglement.. help me validate this analogy! I'm struggling to understand the concept of quantum entanglement. I've distilled my understanding into an analogy, and I need your help to validate it. Here it is: Let's say I receive two envelopes. Both envelopes have this written on them: Hello!... | eng_Latn | 4,065 |
Band gap in semiconductors If one semiconductor is transparent and another is not (in the visible spectrum), what causes that difference? Is it related to their band gap, because that influences which wavelengths they can emit? As an example gallium arsenide is opaque, zinc sulphide isn't. | Why is diamond transparent while graphite is not? Diamond and graphite are both made of the same atom, carbon. Diamond has a tetrahedron structure while graphite has a flat hexagonal structure. Why is diamond transparent while graphite is not (at least not with more than a couple of layers)? | What counts as "observation" in Schrödinger's Cat, and why are superpositions possible? So if I understood correctly, Schrödinger's Cat is a thought experiment that puts a cat inside a box, and there's a mechanism that kills the cat with 50% probability based on a quantum process. The argument is that the cat now must ... | eng_Latn | 4,066 |
How does the red pill work? When Neo takes the red pill all kinds of things start to happen. In the matrix the mirror turns into 'The Blob' and smothers his body, in the real world he claws his way through his pod membrane, a machine suddenly appears and grabs him and looks him over then the control cables are detach f... | Does either pill actually do anything? When Morpheus offers the pill choice to Neo, they are still in the Matrix. That leads me to belive that none of the pills are real thus having no particular effect in the real world. Was it some sort of placebo effect that freed Neo from the Matrix or do the pills have an actual e... | What would be an informative introduction to quantum computing software? I am new to Stack Exchange and am working on a quantum learning platform for minority youth groups (LGBTQ, low-income, at risk, etc). In the question below they are looking for courses on the subject, which I am also interested in, and do plan on... | eng_Latn | 4,067 |
Has anyone tried any quantum computing programming code that shows or demonstrates the advantage of a quantum computer over classical computers? Thanks a lot. | It is generally believed and claimed that quantum computers can outperform classical devices in at least some tasks. One of the most commonly cited examples of a problem in which quantum computers would outperform classical devices is $\text{Factoring}$, but then again, it is also not known whether $\text{Factoring}$ ... | I have been trying to show these two inequalities hold for all positive integers n, but I don't know how to proceed at all... I have tried playing around with them but I didn't find anything helpful. I have also tried induction but I couldn't make it work. | eng_Latn | 4,068 |
Let's say I have a time independent Hamiltonian so my system conserves energy. It's initially in an energy eigenstate with $E=1$ in whatever energy units you like. I measure a different observable that doesn't commute with $H$, then I measure $H$ again. I have some probability now of finding my system in an energy eige... | Consider a particle in a potential well. Let’s assume it’s a simple harmonic oscillator potential and the particle is in its ground state with energy E0 = (1/2) ℏω0. We measure its position (measurement-1) with a high degree of accuracy which localises the particle, corresponding to a superposition of momen... | The new Top-Bar does not show reputation changes from Area 51. | eng_Latn | 4,069 |
It seems that a hidden variables theory could reproduce Bell's experiments results, preserving locality, as long as it accepts that the superposition state(or at least a faux superposition) existed at $t=0$ of the creation of entangled pair. In this case, the question "where and how were the particles previous to the m... | Bell's inequality theorem, along with experimental evidence, shows that we cannot have both realism and locality. While I don't fully understand it, Leggett's inequality takes this a step further and shows that we can't even have non-local realism theories. Apparently there are some hidden variable theories that get ... | It is often stated, particularly in popular physics articles and videos, that if one measures a particle A that is entangled with some other particle B, then this measurement will immediately affect the state of the entangled partner. For example, if Alice and Bob share an entangled pair of electrons and Alice measure... | eng_Latn | 4,070 |
why are qubits such a game changer in quantum computing? Qubits are in a superposition which means that they can currently be both digits of 1 and 0 at the same time BUT this is my question: If Qubits have to be filtered to be used then what makes them better than normal bits after they are filtered? they are going to... | How are qubits better than classical bit if they collapse to a classical state after measurement? Classical computers store information in bits, which can either be $0$ or $1$, but, in a quantum computer, the qubit can store $0$, $1$ or a state that is the superposition of these two states. Now, when we make a "measure... | What are the advantages of 10-bit monitors? To support 10-bit color the following are needed: A monitor supporting it. A GPU supporting it (only AMD FirePro and NVIDIA Quadro support this?). Compatible software. Unless I am mistaken there are very few programs out there supporting 10-bit color. Photoshop is a notable... | eng_Latn | 4,071 |
Logical table of P->Q math statements In a course I had, we have been given two statements P and Q and their "boolean table" : While I completely understand P and Q and P or Q values, I can't understand the first two lines for P->Q, why is the result true even when P is false ? Thank you. | In classical logic, why is $(p\Rightarrow q)$ True if both $p$ and $q$ are False? I am studying entailment in classical first-order logic. The Truth Table we have been presented with for the statement $(p \Rightarrow q)\;$ (a.k.a. '$p$ implies $q$') is: $$\begin{array}{|c|c|c|} \hline p&q&p\Rightarrow q\\ \hli... | Understanding quantum entanglement.. help me validate this analogy! I'm struggling to understand the concept of quantum entanglement. I've distilled my understanding into an analogy, and I need your help to validate it. Here it is: Let's say I receive two envelopes. Both envelopes have this written on them: Hello!... | eng_Latn | 4,072 |
Any alternative to time? Just curious to know. Suppose physicists start from the very beginning, i.e defining the fundamental quantities, figuring out the math etc. So will they see the universe differently than what we have presently, particularly can we obtain any alternative to time? Why is time given such an import... | What is time, does it flow, and if so what defines its direction? This is an attempt to gather together the various questions about time that have been asked on this site and provide a single set of hopefully authoritative answers. Specifically we attempt to address issues such as: What do physicists mean by time? Ho... | What would be an informative introduction to quantum computing software? I am new to Stack Exchange and am working on a quantum learning platform for minority youth groups (LGBTQ, low-income, at risk, etc). In the question below they are looking for courses on the subject, which I am also interested in, and do plan on... | eng_Latn | 4,073 |
Can quantum computers put computer security in jeopardy? There are many articles about quantum computers describing how powerful they are in computing and that they can solve very complicated equations in a short time. One of the biggest security measures that provide safety for computer security is that sometimes it t... | What does a "real" quantum computer need for cryptanalysis and/or cryptographic attack purposes? The cryptographic world has been buzzing the word "quantum" for a while now (even the NSA is currently preparing itself for a post-quantum crypto world) and quantum-related hardware engineering is evolving constantly. For e... | What safety precautions should I take when taking photos in the snow? I’m going to Queenstown, NZ in a couple of weeks and want to take my (very new, very precious) Canon 7D with me. I’ve done a little bit of research on how to protect my baby from cold climate (e.g. ) and found that the biggest problem is probably goi... | eng_Latn | 4,074 |
Proving which Quantum Mechanics interpretation is correct Let's assume that the existence of gravitons is theoretically proven or they are detected by LHC could one interpretaion be proven correct? | Proving which QM interpretation is correct Let's assume that the existence of gravitons is theoretically proven or they are detected by LHC could one interpretaion be proven correct? | Inexact measurement and wavefunction collapse As is usually said, measurement of an observable $q$ leads to collapse of wavefunction to an eigenstate of the corresponding operator $\hat q$. That is, now the wavefunction in $q$ representation is $\psi(q)=\delta(q-q_0)$ where $q_0$ is result of measurement. Now, in real... | eng_Latn | 4,075 |
Derive the Arbitrary Projection Operator | Projection operators are defined below, given an arbitrary state | ψ ⟩ . {\displaystyle |\psi \rangle .}
| Use this magic prop to make objects appear, disappear or transform. | eng_Latn | 4,076 |
Light pulses and energy-time uncertainty principle Suppose we have a monochromatic light beam. We put an obstacle between source and observer and remove it repeatedly by certain frequency such that observer sees an oscillating intensity of light. Will the observer see different frequencies or only the original frequenc... | Uncertainty and wave-trains My textbook and the following extract from feynman's lectures present the same idea regarding wavetrains and uncertainty in their wavelengths. Why is it that a wavetrain confined to some space has an uncertainty in its wavelength or the wave number? Is not a confined wave-train equivalent to... | Understanding quantum entanglement.. help me validate this analogy! I'm struggling to understand the concept of quantum entanglement. I've distilled my understanding into an analogy, and I need your help to validate it. Here it is: Let's say I receive two envelopes. Both envelopes have this written on them: Hello!... | eng_Latn | 4,077 |
Why we can't conserve light? All I made up in my mind about light beeing a wave traveling at vertain speed, made me thing of it like something we could store in tehory. So I would assume if I had a box where the inside is made up completly with mirrors, when sending light in and closing the box, this light would keep... | What longest time ever was achieved at holding light in a closed volume? For what longest possible time it was possible to hold light in a closed volume with mirrored walls? I would be most interested for results with empty volume but results with solid-state volume may be also interesting. | Understanding quantum entanglement.. help me validate this analogy! I'm struggling to understand the concept of quantum entanglement. I've distilled my understanding into an analogy, and I need your help to validate it. Here it is: Let's say I receive two envelopes. Both envelopes have this written on them: Hello!... | eng_Latn | 4,078 |
Which book in Asimov's Foundation series describes a video communication system just like our "Zoom" Long ago I read all the books in Asimov's Foundation series. In one of them, people are living alone or very few at a time on separate worlds that are far apart. They communicate via a video system that I remember as be... | Short sci-fi story about Earth blockaded by other human colonies Like the subject: short sci-fi story about Earth blockaded by other human colonies. The best humans have colonized some stellar systems. But they begin to treat humans of earth like inferiors. A war began, colonies won the war and blockaded the earth, bu... | Understanding quantum entanglement.. help me validate this analogy! I'm struggling to understand the concept of quantum entanglement. I've distilled my understanding into an analogy, and I need your help to validate it. Here it is: Let's say I receive two envelopes. Both envelopes have this written on them: Hello!... | eng_Latn | 4,079 |
How are the photon and electron entangled in this situation? | Creation of entangled electrons | A fiber bundle over Euclidean space is trivial. | eng_Latn | 4,080 |
Understanding the basic concepts of quantum mechanics using a model I'm not an expert and I don't know if already exists something like the following model, but I wrote a simple (mental) model to understand the basic concepts of quantum mechanics. I want to know if this model is valid or not. Red-or-Black (RoB) Card M... | Quantum entanglement vs classical analogy Consider that we have two balls, one white and one black, and two distant observers A and B with closed eyes. We give the first ball to the observer A and the second ball to the observer B. The observers don't know the exact color (state) of their balls, they know only the prob... | How is the no-cloning theorem compatible with the fact that fan-out gates work? I have some difficulty with understanding no-cloning theorem. Simply speaking, according to the theorem, it is not possible to copy a quantum state. On the other hand, CNOT gate can be used as so-called fan-out gate which purpose is to cop... | eng_Latn | 4,081 |
Can Alice encrypt a message to Bob without hiding anything from Eve? I know that if Alice and Bob both have secret-public key pairs, they can use RSA for example. If we remove the possibility that Alice can know anything which Eve doesn't (ie Alice's secret key), is there an algorithm which makes encryption still possi... | How does asymmetric encryption work? I've always been interested in encryption but I have never found a good explanation (beginners explanation) of how encryption with public key and decryption with private key works. How does it encrypt something with one key and decipher it with another key? | Understanding quantum entanglement.. help me validate this analogy! I'm struggling to understand the concept of quantum entanglement. I've distilled my understanding into an analogy, and I need your help to validate it. Here it is: Let's say I receive two envelopes. Both envelopes have this written on them: Hello!... | eng_Latn | 4,082 |
Is there a word for when you run into someone and both of you try to avoid each other and fail, repeatedly? It has most certainly happened to all of us at least once: Two people walking along the same narrow pathway in opposite directions walk into each other. There is room for both to pass each other, but person A s... | Word for the situation of being unable to pass opposing pedestrian, as you both start to step same direction Is there a word or expression in English, which describes the situation, when you can't pass a stranger, who is walking towards you on the street, because you both start to step the same direction? I'm pretty ... | What's wrong with this experiment showing that either FTL communication is possible or complementarity doesn't hold? The assumptions are: Alice and Bob have perfectly synchronized clocks Alice and Bob have successfully exchanged a pair of entangled photons The idea is simply to have Alice and Bob perform the Quant... | eng_Latn | 4,083 |
Modern textbooks on quantum mechanics I'm looking for modern textbooks on quantum mechanics that treat topics such as quantum entanglement , bell's theorem , quantum teleportation , quantum information theory , The Many-world interpretation , decoherence etc . All the textbooks that I can find cover the usual topics on... | Learn QM algebraic formulations and interpretations I have a good undergrad knowledge of quantum mechanics, and I'm interesting in reading up more about interpretation and in particular things related to how QM emerges algebraically from some reasonable real world assumptions. However I want to avoid the meticulous mat... | Do electrons really perform instantaneous quantum leaps? This is not a duplicate, non of the answers gives a clear answer and most of the answers contradict. There are so many questions about this and so many answers, but none of them says clearly if the electron's change of orbitals as per QM can be expressed at a ti... | eng_Latn | 4,084 |
Canonical everyday-life example of a technology that could not work without humans mastering QM in analogy to the application of GR in GPS? The GPS is a very handy example in explaining to a broad audience why it is useful for humanity to know the laws of general relativity. It nicely bridges the abstract theory with ... | Quantum mechanics and everyday nature Is there a phenomenon visible to the naked eye that requires quantum mechanics to be satisfactorily explained? I am looking for a sort of quantic Newtonian apple. | How are quantum gates realised, in terms of the dynamic? When expressing computations in terms of a quantum circuit, one makes use of gates, that is, (typically) unitary evolutions. In some sense, these are rather mysterious objects, in that they perform "magic" discrete operations on the states. They are essentially ... | eng_Latn | 4,085 |
How close are we in achieving computation over reals using quantum qubits? I recently attended a seminar where a professor of quantum cryptography told the audience that one quantum qubit can theoretically store "infinite information". I was very intrigued by this statement, and me being an absolute novice in this doma... | How can infinite information be theoretically encoded or stored in a single qubit? I've just gotten started with Nielsen and Chuang's text, and I'm a little stuck. They mention that theoretically, it would be possible to store an infinite amount of information in the state of a single qubit. I'm not sure I completely c... | Inexact measurement and wavefunction collapse As is usually said, measurement of an observable $q$ leads to collapse of wavefunction to an eigenstate of the corresponding operator $\hat q$. That is, now the wavefunction in $q$ representation is $\psi(q)=\delta(q-q_0)$ where $q_0$ is result of measurement. Now, in real... | eng_Latn | 4,086 |
Magnets quantum locking/levitating How does cooling a magnet allow it to quantum lock/levitate? I have seen it in videos but do not know how it works. | How does quantum trapping with diamagnets work? I just saw demonstration by someone from a Tel Aviv University lab. What they achieved there is mind blowing. I myself own a levitron that uses the Hall effect to levitate a magnet, the problem with that is the magnet must always be flat facing the Hall effect base, any... | How are qubits better than classical bit if they collapse to a classical state after measurement? Classical computers store information in bits, which can either be $0$ or $1$, but, in a quantum computer, the qubit can store $0$, $1$ or a state that is the superposition of these two states. Now, when we make a "measure... | eng_Latn | 4,087 |
Is there any tool or simulator for Topological quantum gates and circuits? I am starting to step into the field of Topological Quantum Information and Computation and am in search of tools which I can use to directly simulate or realize these transformations in a textual or graphical manner. | Topological Circuit Simulator Does something like exist for topological (eg. braided) circuits? Alternatively, any ideas on how @ is getting (or something similar)? | What is time dilation really? Please will someone explain what time dilation really is and how it occurs? There are lots of questions and answers going into how to calculate time dilation, but none that give an intuitive feel for how it happens. | eng_Latn | 4,088 |
Gravitational wave behavior My guestion is since we have now detected gravitational waves can gravitational waves go through interference (ie destructive or constructive interference) with each other like other waves? | What Happens When A Gravitational Wave Interacts With Another One? If two gravitational waves came in contact with each other what would happen? In another question entirely, what happens when a higher gravitational field interacts with a weaker one. | How are quantum gates realised, in terms of the dynamic? When expressing computations in terms of a quantum circuit, one makes use of gates, that is, (typically) unitary evolutions. In some sense, these are rather mysterious objects, in that they perform "magic" discrete operations on the states. They are essentially ... | eng_Latn | 4,089 |
Is there any way to see that $H= p^2 +x^2$ has level-spaced spectrum from the symmetry? I heard that Ken Wilson had an explanation of the level-spacing of the harmonic oscillator spectrum directly from the symmetry of $H$ under interchange of $p$ and $x$, without ladder operators or direct computation. After some tho... | Why are the energy levels of a simple harmonic oscillator equally spaced? The energy level of a simple harmonic oscillator is $E_n=(n+\frac{1}{2})\hbar\omega$. Is there any physical explanation why these levels are equally spaced ($= \hbar\omega$)? Maybe this can be helpful. | What's wrong with this experiment showing that either FTL communication is possible or complementarity doesn't hold? The assumptions are: Alice and Bob have perfectly synchronized clocks Alice and Bob have successfully exchanged a pair of entangled photons The idea is simply to have Alice and Bob perform the Quant... | eng_Latn | 4,090 |
Was Q Created in the very first Star Trek Movie? This question is based off the end of the very first Star Trek Movie, so I will ask it in spoilers in the odd case that you haven't seen it yet. At the end of the movie Kirk asked Bones and Spock if they had just witnessed the making/creation of a new species. duri... | Where did the Q come from, before the Q Continuum? In the Star Trek Universe where did the Q come from? I mean before they were Q in the Q Continuum? In Star Trek Voyager you learn that the race is somewhat intolerant of individualism (in the episode of the Q Civil War) but Q also suggest they have always been Q. Is th... | Understanding quantum entanglement.. help me validate this analogy! I'm struggling to understand the concept of quantum entanglement. I've distilled my understanding into an analogy, and I need your help to validate it. Here it is: Let's say I receive two envelopes. Both envelopes have this written on them: Hello!... | eng_Latn | 4,091 |
Confusion regarding fundamental particles As per standard model, particles like electron and quarks are considered as the elementary particles (no further division into simpler particles possible). Are those particles really elementary or people don't have enough resources (theories, instruments, energy) to break them... | Why do physicists think that the electron is an elementary particle? When we first discovered the proton and neutron, I'm sure scientists didn't think that it was made up of quark arrangements, but then we figured they could be and experiments proved that they were. So, what is it about the electron that leads us to b... | How are qubits better than classical bit if they collapse to a classical state after measurement? Classical computers store information in bits, which can either be $0$ or $1$, but, in a quantum computer, the qubit can store $0$, $1$ or a state that is the superposition of these two states. Now, when we make a "measure... | eng_Latn | 4,092 |
What if n of RSA is same for two people over the network? I was just going through RSA encryption scheme and was trying to figure out how to do all maths. I was suddenly struck by the question that (e,n) is public to the people. How easy it becomes to attack one's system if you find out that you are using same n as som... | Using same modulus for RSA I know that there exist some attack when using same modulus. But with a little modification, $m$ is the plain-text $N$ is the RSA modulus $r_1, r_2$ is the random padding $e, s$ is the public exponent $C_e, C_s$ is the cipher-text encrypt as follow $$С_e = (m + r_1)^e \bmod N$$ $$С_s ... | Understanding quantum entanglement.. help me validate this analogy! I'm struggling to understand the concept of quantum entanglement. I've distilled my understanding into an analogy, and I need your help to validate it. Here it is: Let's say I receive two envelopes. Both envelopes have this written on them: Hello!... | eng_Latn | 4,093 |
I don't understand why quantum entanglement seems so surprising to physicists in the case of communication. Let us say we take a pair of shoes, and put the two shoes in two separate boxes, and shoot one of the box into a black hole while holding the other box at the other end of the universe. If I were to open the bo... | I'm struggling to understand the concept of quantum entanglement. I've distilled my understanding into an analogy, and I need your help to validate it. Here it is: Let's say I receive two envelopes. Both envelopes have this written on them: Hello! Open this letter... If the paper inside is red, then other envelo... | How do we show that equality holds in the triangle inequality $|a+b|=|a|+|b|$ iff both numbers are positive, both are negative or one is zero? I already showed that equality holds when one of the three conditions happens. | eng_Latn | 4,094 |
I was wondering, whether there are any problems that we already know are difficult to solve for a quantum computer, and that we could potentially use in cryptography, just as we do now with e.g. the factorization of integers? | Quantum computers are known to be able to crack a broad range of cryptographic algorithms which were previously thought to be solvable only by resources increasing exponentially with the bit size of the key. An example for that is . But, as far I know, not all problems fall into this category. On , we can read Re... | It is generally believed and claimed that quantum computers can outperform classical devices in at least some tasks. One of the most commonly cited examples of a problem in which quantum computers would outperform classical devices is $\text{Factoring}$, but then again, it is also not known whether $\text{Factoring}$ ... | eng_Latn | 4,095 |
In particle in square potential barrier problem, we can easily find that some probabilities exist which express how many particles can go beyond of the potential wall. So my question is that, can we find some particles in the potential wall - square of wave function's norm really means probability of find a particle ... | I understand that if a particle approaches a finite potential barrier of height $V_0$ with energy $E < V_0$, there is still a finite probability of finding the particle on the other side of the barrier due to quantum tunneling. My question is, since the wavefunction is nonzero inside the barrier region, is it possi... | Why massless particles have zero chemical potential? | eng_Latn | 4,096 |
I realized that Quantum Random Access Memory (qRAM) was proposed to make quantum computers more similar to classical one. Currently quantum computers have very constrained memory, given only quantum registers on quantum processors can be used for an algorithm to run. It is true that e.g. Qiskit language allows to use R... | Presently, how much information can a quantum computer store, in how many qubits? What restrictions are there and how does it vary across realizations (efficiency of data storage, ease of reading and writing, etc)? | I have forgotten the password or username for my Google account, or I'm unable to access my account for other reasons. How can I recover my account? (This Q&A is meant as a general description for all Google and Gmail username/password questions. See: ) | eng_Latn | 4,097 |
I'm a complete newbie to Quantum Theory, but I want to know more, so I've been watching few YouTube videos (an example below). All videos I've watched explain, that when an entangled particle has its spin measured, it will instantaneously communicate its measurement with its entangled partner, so that when it too i... | I have never found experimental evidence that measuring one entangled particle causes the state of the other entangled particle to change, rather than just being revealed. Using the spin up spin down example we know that one of the particles will be spin up and the other spin down, so when we measure one and find it i... | It is often stated, particularly in popular physics articles and videos, that if one measures a particle A that is entangled with some other particle B, then this measurement will immediately affect the state of the entangled partner. For example, if Alice and Bob share an entangled pair of electrons and Alice measure... | eng_Latn | 4,098 |
I saw a video in which a guy from IBM was explaining (very generally) quantum computing, it's difference with classical computing etc. The talk was not technical at all, it was intended for a broad audience. At some point he told that, if we need to represent our position on the planet with only one bit, we could onl... | I've just gotten started with Nielsen and Chuang's text, and I'm a little stuck. They mention that theoretically, it would be possible to store an infinite amount of information in the state of a single qubit. I'm not sure I completely comprehend this. Here's how I rationalized it: You take all the information you w... | Compared to, for example, completing 5 bounties in each of 5 different games. | eng_Latn | 4,099 |
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