question stringlengths 37 38.8k | group_id stringlengths 2 6 | sentence_embeddings listlengths 768 768 |
|---|---|---|
<p>A typical problem where we exploit the <a href="http://en.wikipedia.org/wiki/Uniqueness_theorem_for_Poisson%27s_equation" rel="nofollow">uniqueness theorem</a> towards a solution, is finding the potential outside two cylindrical parallel conducting wires (at potentials $V_0$ and $-V_0$) extending to infinity. (For e... | g11849 | [
0.06588730216026306,
0.04321569949388504,
-0.016891732811927795,
-0.0499453991651535,
0.06483634561300278,
-0.024742117151618004,
-0.030169766396284103,
0.0027108516078442335,
-0.029929280281066895,
0.012659048661589622,
-0.049873236566782,
-0.014441289938986301,
-0.07488018274307251,
0.00... |
<p>I want to calculate the Wald functional for arbitrary higher curvature Lagrangians - like getting equation 6.31 from 6.30 in this <a href="http://arxiv.org/pdf/1312.7856v1.pdf" rel="nofollow">paper</a>.
A priori the above looks like an extremely complicated calculation!</p>
<p>Or is there a trick or a software poss... | g11850 | [
0.043810855597257614,
-0.035105280578136444,
-0.02887619473040104,
-0.05762738361954689,
-0.007588231470435858,
-0.02169334888458252,
0.006387021392583847,
0.004116784781217575,
-0.04981178790330887,
0.015393833629786968,
-0.03125036507844925,
0.04585834965109825,
0.1111985370516777,
0.009... |
<p>There is a momentum associated with the em field that ensures the conservation of total momentum for a system of interacting charges. </p>
<p>Can the same be done in an analagous way to ensure Newton's third law is also true?</p> | g11851 | [
0.0719430148601532,
-0.01919235661625862,
0.0044547622092068195,
0.009185509756207466,
0.09921479970216751,
0.0369100458920002,
-0.03916112333536148,
-0.023381518200039864,
-0.0032663897145539522,
0.06422822177410126,
-0.016845455393195152,
-0.05160176381468773,
-0.027334382757544518,
0.00... |
<p>The only way to describe the electron radius that I found in literature is the "classical electron radius".
Is it possible to experimentally measure this? Is there a better way to describe the electron size (and in general, the size of any other elementary particle)?</p> | g11852 | [
-0.017279693856835365,
0.03414646163582802,
0.014075424522161484,
-0.06537271291017532,
-0.008056927472352982,
-0.03736069053411484,
-0.05188971012830734,
0.020280785858631134,
-0.035919640213251114,
-0.0028983422089368105,
0.03111705370247364,
0.03112652711570263,
-0.001822435762733221,
0... |
<p>In Pauli theory the components of two-component wavefunction were interpreted as probability amplitudes of finding the particle in particular spin state. This seems easy to understand.</p>
<p>But when talking about Dirac equation, we have four-component wavefunction, two of which correspond to usual spin components... | g11853 | [
0.01662582717835903,
-0.05277413874864578,
-0.009535503573715687,
-0.03398513048887253,
0.05093465745449066,
-0.022360417991876602,
0.08776401728391647,
0.033848412334918976,
-0.019252128899097443,
0.0068531096912920475,
0.009546170942485332,
-0.012847060337662697,
0.07307988405227661,
-0.... |
<p>Water expands when it heats up. If you heat water in a container that prevents it from expanding, will its temperature top out -- maybe around the boiling point?</p>
<p>And if not, will it still turn to gas without room to expand?</p> | g11854 | [
0.017127208411693573,
0.03528118506073952,
0.03367016464471817,
0.07309266924858093,
-0.095174141228199,
0.013887311331927776,
-0.020241614431142807,
0.007032778579741716,
-0.04096829891204834,
-0.026136185973882675,
0.01569758728146553,
0.03344646096229553,
0.0327967070043087,
-0.00492233... |
<p>The governments of Earth have embarked on an experiment to place a massive ball of water in orbit. (umm... special water that doesn't freeze)</p>
<p>Imagine this to be a fluid with a given density, $\rho$ ($kg/m^3$), surface tension, $\sigma$ ($J/m^2$), and formed in a sphere of radius $R$ ($m$). I think that the ... | g11855 | [
0.04313008114695549,
0.05677836760878563,
-0.000815645616967231,
-0.04587915539741516,
-0.0007240147679112852,
0.05909215658903122,
0.0013841044856235385,
0.0020302089396864176,
-0.01917048916220665,
-0.05881216377019882,
0.026165150105953217,
0.0402848944067955,
-0.005709982011467218,
0.0... |
<p>In field theory one can define a time reversal operator T such that $T^{-1} \phi (x) T = \phi (\mathcal T x)$. It is then proved that T must be <a href="http://en.wikipedia.org/wiki/Antiunitary_operator" rel="nofollow">antiunitary</a>: $T^{-1} i T = -i$.</p>
<p>How is this equation to be understood? If $i$ is just... | g11856 | [
-0.023485969752073288,
0.06172241270542145,
-0.03186783939599991,
0.016429651528596878,
0.08326487243175507,
-0.03271147608757019,
0.05685953423380852,
0.01817118003964424,
-0.026160018518567085,
0.03271659091114998,
-0.03877446427941322,
0.06640531867742538,
0.015221652574837208,
-0.03497... |
<p>How do I add the spin angular momentum of massless particles, like photons, where only the transverse polarizations are allowed?</p>
<p>If all three polarizations were allowed, this would be an easy exercise: you'd get $S=0,1,2$ states. But some of these states clearly aren't allowed for purely transverse photons:... | g11857 | [
-0.037203337997198105,
-0.020606186240911484,
-0.005212235730141401,
-0.015118437819182873,
0.04195350781083107,
-0.003447755239903927,
-0.007473859470337629,
0.05737088620662689,
0.04076087847352028,
0.005359264090657234,
0.011392882093787193,
0.003470518859103322,
-0.0068103251978755,
-0... |
<p>In quantum scattering theory, Green's Function is defined as [1]
$$G_0(z)=(z-H_0)^{-1},$$
$$G(z)=(z-H)^{-1},$$
where $H_0$ and $H=H_0+V$ are separately non-interacting and interacting Hamiltonian. $V$ is interaction.<br/>
One can then use the identity
$$\tag{1}V=G_0^{-1}-G^{-1},$$
to obtain <a href="http://en.wikipe... | g11858 | [
0.009565034881234169,
-0.007751605939120054,
0.0015944185433909297,
0.026240037754178047,
0.07189890742301941,
-0.01971723698079586,
0.012330654077231884,
-0.008160041645169258,
-0.022051183506846428,
-0.030302878469228745,
-0.032376814633607864,
0.0015482731396332383,
0.0290504340082407,
... |
<p>Is there anyway to use a scientific instrument to measure the density of electron around the atomic orbital? Please list both old way and more modern ways.</p> | g11859 | [
-0.024763088673353195,
0.0002366348635405302,
0.013147780671715736,
-0.03938059136271477,
0.021362019702792168,
0.014714538119733334,
-0.02905205823481083,
-0.023493994027376175,
-0.0005647993530146778,
-0.004734423477202654,
0.07819334417581558,
0.03045307844877243,
0.05099254846572876,
0... |
<p>I have a particle that has a mass around $(760\pm10)~MeV/c^2$ but I do not know what kind of particle it is. <a href="http://pdg.lbl.gov/2013/tables/contents_tables.html" rel="nofollow">This links me to</a> some tables that have data on all sorts of subatomic particles but it is a bit daunting to go through and fig... | g11860 | [
0.015969013795256615,
-0.004825656767934561,
0.030707180500030518,
-0.08461954444646835,
0.017961610108613968,
-0.03779056668281555,
0.005466358736157417,
-0.0718873143196106,
-0.0549805648624897,
-0.02123405784368515,
0.037713535130023956,
0.06889534741640091,
-0.00542938569560647,
-0.032... |
<p>As a starting quantum physicist I am very interested in reasons why does <a href="http://en.wikipedia.org/wiki/Pauli_exclusion_principle" rel="nofollow">Pauli's Exclusion Principle</a> works. I mean standard explanations are not quite satisfying. Of course we can say that is because of fermionic nature of electrons ... | g11861 | [
0.05369051918387413,
0.09207645058631897,
-0.0018245079554617405,
-0.019437076523900032,
0.02648218721151352,
-0.011797480285167694,
0.05847761034965515,
0.022011160850524902,
-0.0013829938834533095,
-0.006892114877700806,
-0.04422171413898468,
0.0008285394287668169,
-0.015170312486588955,
... |
<p>let us consider that i have a voltaic cell in an open circuit that has copper plate at higher potential w.r.t zinc plate. Now my query is, since the electrolyte separating them is a conducting medium, the positive and negative charges on the electrodes must get neutralised immediately(i think so)...But it doesnt hap... | g11862 | [
0.041731614619493484,
0.004653968848288059,
-0.014581604860723019,
0.02608047053217888,
0.09136611968278885,
0.05639389529824257,
0.03126049041748047,
0.04285449907183647,
0.0030034200754016638,
0.011921040713787079,
-0.04185689613223076,
0.05905929580330849,
-0.038954947143793106,
0.01828... |
<p>I'm struggling with the following question:</p>
<blockquote>
<p><em><strong>Question 6</strong> A planet of mass $m$ moves under the gravitational attraction of a central star of mass $M$. The equation of motion of the planet is</em></p>
<p>$$\ddot{\mathbf{r}} = -\mathcal{G}\frac{(M + m)}{r^3}\mathbf{r}$$</p... | g11863 | [
-0.012059623375535011,
0.023567097261548042,
-0.005893851164728403,
0.004388266243040562,
0.01772170700132847,
0.016265401616692543,
0.029485829174518585,
-0.004584833048284054,
-0.03494836762547493,
0.0009072769898921251,
0.0038131980691105127,
0.06724374741315842,
0.014579675160348415,
-... |
<p>A light switches on and off at a fast rate, with equal time off and on, why do we see a light that appears only on rather than only off?</p> | g11864 | [
0.06496409326791763,
0.06371933966875076,
0.0010499712079763412,
-0.003452559933066368,
0.03937830775976181,
-0.040800631046295166,
0.04276306927204132,
0.07894790172576904,
-0.022046172991394997,
-0.061606645584106445,
0.07312759011983871,
0.029043015092611313,
0.05140934884548187,
0.0956... |
<p>While I was considering an answer to <a href="http://physics.stackexchange.com/questions/64872/why-doesnt-light-kill-me">this question</a>, I wondered how much light that enters the atmosphere reaches the ground without colliding with air molecules—if any. I've taken a good bit of physics course (not optics, yet), b... | g11865 | [
0.008220969699323177,
-0.006460886914283037,
0.0039640506729483604,
0.031982116401195526,
-0.006566183641552925,
0.046672459691762924,
0.027309857308864594,
0.02188972197473049,
-0.016850370913743973,
-0.038796618580818176,
0.024278294295072556,
-0.02032202109694481,
0.01070521678775549,
-... |
<p>I know it's a newbie question but I was wondering about how the principle of locality and the speed of light's limit fit with the phenomena of quantum entanglement?</p>
<p>I've read that, due to Bell's theorem, the quantum entanglement does not violate the two principle above, but how it is possible if when entangl... | g11866 | [
-0.00416198093444109,
0.06586430966854095,
0.004206196870654821,
-0.024051083251833916,
0.04577641934156418,
-0.005089189391583204,
-0.012335238046944141,
0.027626508846879005,
0.012152069248259068,
0.020404603332281113,
0.01686955615878105,
0.025134239345788956,
-0.006455940194427967,
-0.... |
<p>What are the differences between Classical <a href="http://en.wikipedia.org/wiki/Monte_Carlo_method" rel="nofollow">Monte Carlo</a> methods and <a href="http://en.wikipedia.org/wiki/Quantum_Monte_Carlo" rel="nofollow">Quantum Monte Carlo</a> methods in condensed matter physics? If one want to study strongly correlat... | g11867 | [
0.0636867806315422,
0.017854249104857445,
0.015919361263513565,
-0.008312703110277653,
0.017084425315260887,
0.008430900052189827,
0.024086078628897667,
0.00025392926181666553,
-0.010162594728171825,
-0.008909138850867748,
-0.020464206114411354,
0.012149889022111893,
0.04482776299118996,
-... |
<p>Let's assume that we have a mechanism for producing EM radiation suspended in the air, and that that mechanism itself is invisible to the naked eye (e.g. a microscopic light bulb on a microscopic wire or a suspended molecular reaction giving off energy.) When off, the light source would not be visible. When turned o... | g11868 | [
0.0034274666104465723,
0.008229326456785202,
0.018194379284977913,
0.003561877179890871,
-0.04608587175607681,
0.060089655220508575,
-0.00440481211990118,
0.03497665375471115,
-0.01441019307821989,
0.015487389639019966,
0.010932737961411476,
0.05819687992334366,
0.05842700973153114,
-0.003... |
<p>Rydberg blockade is a phenomena in 3 or more level systems of Rydberg dressed atoms.</p> | g11869 | [
-0.021261485293507576,
0.06155912205576897,
-0.017342129722237587,
-0.010059530846774578,
-0.048865776509046555,
0.06707536429166794,
0.0002497563837096095,
0.037094421684741974,
0.0511544793844223,
0.011730246245861053,
-0.046550098806619644,
0.049628324806690216,
-0.03797611594200134,
0.... |
<h1><strong>Question:</strong></h1>
<p>How can you show the inconsistency of regularization by dimensional reduction in the $\mathcal{N}=1$ superfield approach (without reducing to components)?</p>
<hr>
<h1><strong>Background and some references:</strong></h1>
<p>Regularization by dimensional reduction (DRed) was i... | g11870 | [
0.0242951437830925,
-0.0031295393127948046,
0.004516448359936476,
0.008413106203079224,
-0.0059681301936507225,
-0.0022893710993230343,
0.0930401086807251,
0.054639969021081924,
-0.03580909222364426,
-0.026752769947052002,
-0.03188588097691536,
-0.010540333576500416,
0.02928655967116356,
0... |
<p>In history we are taught that the Catholic Church was wrong, because the Sun does not move around the Earth, instead the Earth moves around the Sun.</p>
<p>But then in physics we learn that movement is relative, and it depends on the reference point that we choose.</p>
<p>Wouldn't the Sun (and the whole universe) ... | g205 | [
0.022596891969442368,
0.0032435047905892134,
0.009563799016177654,
0.024809401482343674,
0.039389271289110184,
0.032904934138059616,
0.058036092668771744,
-0.010601518675684929,
-0.028533995151519775,
-0.006932137534022331,
0.04816856235265732,
0.005228967405855656,
0.06681507080793381,
0.... |
<p><strong>Introduction and Notation</strong> </p>
<p>Let $\phi(\vec{x})$ be the real Klein-Gordon (quantum) field, written as:</p>
<p>$$\phi(\vec{x})=\int\frac{d^3p}{(2\pi)^3}\frac{1}{\sqrt{2\omega_{p}}}\left(a_{\vec{p}}+a^{\dagger}_{-\vec{p}} \right)e^{i\vec{p}\cdot\vec{x}} $$</p>
<p>where $\omega_{p}=\sqrt{|\vec{... | g11871 | [
0.02197117917239666,
-0.010938982479274273,
-0.007730519864708185,
-0.042757872492074966,
0.05536692589521408,
0.006941437255591154,
-0.006697219796478748,
-0.011415624991059303,
-0.009058994241058826,
0.031144216656684875,
-0.031792014837265015,
-0.0052773780189454556,
-0.04454817250370979,... |
<p>In a two level atomic system (<a href="http://en.wikipedia.org/wiki/Rabi_cycle" rel="nofollow">Rabi oscillating</a> problem) the perturbative potential is oscillating / sinusoidal because it comes from the electric field from the laser. </p>
<p>Now stark effect is the phenomena of splitting of energy levels in atom... | g11872 | [
0.018982382491230965,
0.044387154281139374,
-0.005909190513193607,
0.026875576004385948,
0.05547761917114258,
0.06321068853139877,
-0.015268566086888313,
0.06485752761363983,
0.02494211681187153,
0.011402515694499016,
-0.0323135107755661,
0.020838800817728043,
0.0003693205362651497,
-0.009... |
<p>Say you have a vacuum tube, such as the kind used in old amplifiers, wherein electrons are accelerated from the cathode to the anode through an electric field. Presuming, for the sake of argument, that electrons coming off of the cathode have a zero energy, and the anode, made of a material with a work function of 4... | g11873 | [
0.024784568697214127,
0.036299627274274826,
0.0076855262741446495,
0.08410549908876419,
0.018383674323558807,
0.03639429435133934,
-0.02024105004966259,
0.024198142811655998,
-0.03701218590140343,
0.0012588294921442866,
-0.009952404536306858,
0.0845327228307724,
0.022590840235352516,
-0.02... |
<p>This is a rather broad question. Does anyone know of good video lectures for graduate level classical electrodynamics? </p> | g629 | [
0.019737640395760536,
0.05047180503606796,
-0.008913461118936539,
-0.0259445421397686,
0.02930157259106636,
0.07102309912443161,
0.032779593020677567,
0.012053483165800571,
0.02912849560379982,
0.006205379031598568,
0.01877715066075325,
0.034362077713012695,
0.031150085851550102,
0.0467361... |
<blockquote>
<p><code>Question</code>: An operator $A$ is in a particular basis $|a_i\rangle$ (where $i=1,2$), and is represented by
$$A=\begin{pmatrix} 0 & -i \\ i &0 \end{pmatrix}$$
Now, define two new basis vectors $|b_i\rangle$ by
$$\langle a_i | b_1\rangle =\frac{1}{\sqrt{2}}\begin{pmatrix} 1 \\ 1 ... | g11874 | [
0.03895993530750275,
-0.041259635239839554,
0.01210989523679018,
-0.017581157386302948,
0.049137476831674576,
-0.08552621304988861,
0.07975165545940399,
0.00032586706220172346,
-0.00908304750919342,
0.01799086108803749,
-0.0375300794839859,
0.050275273621082306,
0.0030735244508832693,
0.00... |
<p>To cut an apple, do I need more pressure or more force? When we want to destroy the intermolecular bonds, don't we need more force ? </p> | g11875 | [
0.005635804962366819,
0.0607859268784523,
0.018295321613550186,
0.012199233286082745,
0.0395691879093647,
-0.03599930554628372,
-0.012249372899532318,
0.00540290167555213,
-0.04484205320477486,
-0.01722237840294838,
0.023860065266489983,
-0.020741941407322884,
-0.06041586399078369,
-0.0341... |
<p>Rank two Cartesian tensors can be decomposed into $L=0,1,2$ spin like things 3x3=1+3+5.</p>
<p>But the second equation below does not transform like a "tensor", it looks more like a vector transform in five dimensional Cartesian coordinate.</p>
<p>$$\mathfrak{D}^{+}(R)V_{i}\mathfrak{D}(R) = \sum_{j=1,2,3}R_{ij}V_... | g11876 | [
0.01367725245654583,
-0.016324909403920174,
-0.01556391455233097,
-0.042862579226493835,
-0.0023418336641043425,
-0.004748753737658262,
0.018723830580711365,
-0.002443289617076516,
-0.02633683569729328,
0.011542028747498989,
-0.06137349456548691,
0.009653424844145775,
0.03777804970741272,
... |
<p>I think that both force (number of newtons) and power (p=ui(?)) implies that there is energy so we can't have force without energy and we can't have power without energy(?)</p>
<p>But can there be energy that is energy and no force and no power?</p> | g11877 | [
0.011423355899751186,
0.03616565465927124,
0.018713580444455147,
0.014029121957719326,
-0.012763741426169872,
-0.02813330665230751,
-0.050416264683008194,
0.03887075558304787,
-0.01747748628258705,
-0.039732713252305984,
0.03321624919772148,
-0.037035632878541946,
-0.035793934017419815,
-0... |
<p>In the question <a href="http://physics.stackexchange.com/questions/2901/is-there-a-black-hole-in-the-centre-of-the-milky-way">Is there a black hole in the centre of the Milky Way?</a> the answer by Motl <em>seems</em> to all but say the existence of that black hole is a fact (see also <a href="http://physics.stacke... | g11878 | [
0.05325422063469887,
0.01708647981286049,
0.030451122671365738,
-0.01817629672586918,
0.06222531571984291,
0.0028557635378092527,
-0.001248326268978417,
0.028882453218102455,
-0.05326616391539574,
0.0036828836891800165,
0.09065677970647812,
-0.017511045560240746,
0.013544701039791107,
-0.0... |
<p>Imagine that there's a light ray, with source at point <strong>A</strong>, and it's directed towards point <strong>B</strong> (which is very far from point <strong>A</strong>) and it continues for a huge distance.
How will an observer at point <strong>B</strong> perceive the light ray if it gets moved be a certain a... | g11879 | [
0.022445857524871826,
0.005004044156521559,
-0.0017437869682908058,
0.013484898954629898,
0.011485484428703785,
0.03026636131107807,
0.032053861767053604,
0.039066482335329056,
-0.0070239948108792305,
-0.037520620971918106,
0.04104435071349144,
0.05060811713337898,
0.07035555690526962,
-0.... |
<p>I read an article about possibility of existence of multiverse and came up with a conflicting view with one of the sentences written in the article which goes as follows:</p>
<blockquote>
<p>"If space-time goes on forever, then it must start repeating at some point, because there are a finite number of ways parti... | g11880 | [
0.015643110498785973,
0.09725020825862885,
0.004923983011394739,
-0.044388893991708755,
0.021715650334954262,
-0.01638380065560341,
0.0072390190325677395,
-0.002212893683463335,
-0.017806436866521835,
-0.02032574824988842,
-0.032186366617679596,
-0.0006598458276130259,
0.0095386803150177,
... |
<p>When a gas at normal conditions (<strong>1atm, 273K, 22.4L</strong>) we say like the $$\frac{PV}{T} = 0.0820...$$
And by the know equation: $$PV = nRT$$
Where R is equals to $0.08205...$ and $n$ is the number of mols of the substance.
When we want to compare a previous state of a gas with its next state, we use the ... | g11881 | [
-0.0016599521040916443,
-0.0559077151119709,
-0.0014158617705106735,
0.019880827516317368,
0.0029008681885898113,
-0.06423202902078629,
-0.0062955934554338455,
-0.002656943630427122,
-0.02021346054971218,
-0.009940121322870255,
-0.023529088124632835,
0.016094578430056572,
0.03374321013689041... |
<p>We commonly investigate the properties of SU(2) on the basis of SO(3). However, I want to directly calculte the infinitesimal generator of SU(2) according to the definition $$X_{i}=\frac{\partial U}{\partial \alpha_{i}}$$ from Lie group theory. But, where are the problems of the methods I used below?</p>
<p>First, ... | g11882 | [
0.016213389113545418,
0.014253439381718636,
-0.004306048154830933,
-0.06871210783720016,
-0.01800750009715557,
0.013757064007222652,
0.009074976667761803,
0.07180096209049225,
-0.06741222739219666,
0.021974019706249237,
-0.009141114540398121,
-0.009062062948942184,
0.007598496042191982,
0.... |
<p>I saw somewhere that an electromagnetic field would cause a substance to let off thermal energy, ultimately resulting in the substance to cool really quickly.</p>
<p>If this is possible, does the strength of the magnetic field correlate with the rate of cooling? What are the physics behind this phenomena?</p> | g11883 | [
0.06940735131502151,
0.03920808434486389,
0.016499556601047516,
-0.031409163028001785,
0.058990105986595154,
-0.011010355316102505,
-0.0204987283796072,
0.06767872720956802,
-0.022754337638616562,
0.009054858237504959,
-0.027288468554615974,
-0.003941910807043314,
0.00043998160981573164,
-... |
<p>Assuming I have a spacecraft which is $30,000\,\mathrm{kg}$ (roughly the size of the Apollo spacecraft).</p>
<p>If I take a comet and (theoretically) electrolize it perfectly to hydrogen and oxygen. I know have $2.2\times10^{14}\,\mathrm{kg}$ of $\mathrm{H_2}$ and $\mathrm{O_2}$. </p>
<p>Now I burn it. Assuming pe... | g11884 | [
-0.009379585273563862,
0.09198318421840668,
0.0027338347863405943,
0.031657591462135315,
0.003847384126856923,
-0.00947591569274664,
-0.0035380416084080935,
0.0356280542910099,
-0.05498652905225754,
-0.006840960588306189,
0.024787964299321175,
0.040929555892944336,
-0.005242191255092621,
0... |
<p>Assuming normal spacecraft and space objects (no neutron stars, black holes, etc). To what speed can a spacecraft accelerate using <a href="http://en.wikipedia.org/wiki/Gravity_assist">gravity-assist</a>?</p>
<p>For example, if a spacecraft is moving at relativistic speeds, it probably won't get seriously sped up b... | g11885 | [
-0.0116764260455966,
0.10277654230594635,
0.008479819633066654,
0.018878750503063202,
0.02690473012626171,
0.008796905167400837,
-0.018280742689967155,
-0.017278088256716728,
-0.056084152311086655,
-0.011616121977567673,
0.08556823432445526,
0.027217116206884384,
0.010105805471539497,
-0.0... |
<p>Imagine a mirror house i.e. completely made of mirror with no traces of whatsoever light absorbent.</p>
<p>Now, you introduce a light beam into that room and observe somehow through a hole.</p>
<p>Would the room be </p>
<ol>
<li>complete dark - since nothing is actually absorbing it!!
or would it be</li>
<li>ve... | g11886 | [
0.0014223007019609213,
0.00890862476080656,
0.0018916766857728362,
-0.020784759894013405,
0.015731964260339737,
0.0335821770131588,
0.019205179065465927,
0.09089062362909317,
0.015617219731211662,
-0.020509622991085052,
0.023284507915377617,
0.018791867420077324,
0.02734282612800598,
0.034... |
<p>In my physics textbook it describes the events at the beginning of the Universe. I'm confused about the order at a certain point. It says that at some point primordial helium is created, then it says that later atoms are formed. Isn't primordial helium made of atoms? </p>
<p>Thank you :) </p> | g11887 | [
0.018666638061404228,
-0.007266841363161802,
0.021245339885354042,
-0.0342029333114624,
0.06273539364337921,
0.06430475413799286,
-0.031686391681432724,
0.04284321144223213,
-0.030286461114883423,
-0.04133106395602226,
-0.06795419007539749,
0.02790042944252491,
-0.0194321870803833,
-0.0075... |
<p>If a diatomic gas like Hydrogen has 6 maximum degrees of freedom why its molar heat capacity reaches at high temperatures $C_V = \frac{7}{2} R$ and not $C_V = \frac{6}{2} R= 3R$?</p>
<p><a href="http://theory.phy.umist.ac.uk/~judith/stat_therm/img711.gif" rel="nofollow">molar heat capacity of hydrogen</a></p> | g11888 | [
0.0424688383936882,
0.007054776418954134,
-0.006895194761455059,
0.0787319615483284,
-0.027530308812856674,
-0.012639022432267666,
-0.047785285860300064,
0.06793658435344696,
-0.0428338497877121,
0.008280870504677296,
-0.018355155363678932,
-0.009704490192234516,
0.03071579523384571,
0.022... |
<p>I'm an undergraduate physics without much quantum mechanics <em>at all</em> under my belt. I'm studying functional analysis, and I want to know whether or not this will be useful for me in theoretical physics in the future. Some perceived benefits of studying functional analysis are:</p>
<ul>
<li>It gives familiari... | g374 | [
-0.005117092281579971,
-0.006693982984870672,
0.021811800077557564,
-0.029490681365132332,
0.015827400609850883,
-0.04779255762696266,
0.03694131225347519,
0.0014310440747067332,
0.015093893744051456,
-0.06758473813533783,
-0.001325329882092774,
-0.040060997009277344,
0.04347597435116768,
... |
<p>Also, what's the proper stack exchange site to ask this on? mechanics.stackexchange seems to be for motorvehicles.</p>
<p>I'm designing an automatic guitar tuner that clamps onto my acoustic guitar. The tuning key handles will be removed and replaced with one that has a brass gear on it. Each tuning key gear is ... | g11889 | [
-0.001764811691828072,
0.03131463751196861,
0.005012104753404856,
-0.007737325504422188,
-0.01453321985900402,
-0.021864192560315132,
0.012646754272282124,
-0.042070452123880386,
-0.025271248072385788,
-0.020390987396240234,
-0.0664970800280571,
0.00591414887458086,
0.01333948876708746,
-0... |
<p>When I view most glass from the side it's green which I've found out is due to impurities in the glass specifically from iron oxide.
Why is it when I view the larger face from an oblique angle, it isn't nearly as green? <br><br>I cannot personally notice any different on the piece I have next to me even when I hold ... | g11890 | [
0.035069990903139114,
0.006442127749323845,
0.006679879035800695,
0.016880972310900688,
0.03376057744026184,
0.015047900378704071,
0.03922860324382782,
0.04747345298528671,
-0.005099874455481768,
0.011506485752761364,
0.07974810153245926,
0.05292906239628792,
0.018487511202692986,
-0.01625... |
<p>I was thinking about the question I posted yesterday, and I thought of a better way to ask it.</p>
<p>I'm trying to figure out why QM necessitates "pure randomness". Assume you have a photon that has a hidden variable. This hidden variable is a pseudorandom number generator $f(t) \in \mathbb{R}$ such that $0 \leq... | g11891 | [
-0.01745343953371048,
0.018362363800406456,
0.008690775372087955,
-0.04799007251858711,
0.009276280179619789,
-0.01166138332337141,
0.039787765592336655,
0.026104643940925598,
0.01944953016936779,
0.0037492637056857347,
-0.01880466751754284,
0.03034508228302002,
-0.04410729929804802,
0.000... |
<p>I recently had question, can 2 elementary particles be "attached" together using Strong and weak nuclear forces to create a <a href="http://en.wikipedia.org/wiki/Bound_state" rel="nofollow">bound state</a>. For example can Electron and some other stable elementary particle such as Strange Quark be formed to gather w... | g11892 | [
-0.012675161473453045,
-0.010749753564596176,
0.0037822057493031025,
-0.01384017150849104,
0.0411515012383461,
0.007170920260250568,
-0.08780726045370102,
-0.017011962831020355,
0.020864883437752724,
-0.0642528384923935,
-0.0026250488590449095,
-0.005107636097818613,
-0.0016901422059163451,
... |
<p>So for the Stern-Gerlach apparatus, we assume that we either have a particle spin up or spin down. We also have the varying field, $\partial B/\partial z$. This initial configuration results in the particle wither going to plus $\hbar$ or minus $\hbar$. </p>
<p>Suppose instead of having spin up/down in the z dir... | g11893 | [
0.03391473740339279,
-0.024473000317811966,
-0.003303440287709236,
0.04053124040365219,
0.05359785258769989,
0.017312465235590935,
0.11073333770036697,
0.002625789726153016,
0.007920447736978531,
-0.011819636449217796,
-0.02064988762140274,
0.056445054709911346,
0.019733266904950142,
-0.00... |
<p><img src="http://i.stack.imgur.com/pUJyJ.png" alt="image_of_problem"></p>
<p>I have no clue on how to approach this. The professor only discussed centripetal acceleration and angular velocity (As in $2πr\over T$ $= ωr$). Does the acceleration along the axis of the drum act in the same way that centripetal accelerat... | g11894 | [
0.07487305253744125,
0.014094783924520016,
0.002546006115153432,
0.014618960209190845,
0.0371689535677433,
-0.010005949065089226,
0.12440389394760132,
0.03786611184477806,
-0.02736017107963562,
-0.004923979286104441,
-0.029917597770690918,
0.037948764860630035,
0.02390795759856701,
0.00782... |
<p>This question is the inverse of: "Could an object orbit while moving at twice the speed, but at the same distance, if it had half the mass?"</p>
<p>I'm curious about the nature of orbits, but am not well enough versed in mathematics to understand Kepler's laws well. I have been wondering if the mass of a planet and... | g375 | [
-0.0071193682961165905,
0.021995939314365387,
0.017884409055113792,
0.04233347252011299,
0.05010753870010376,
-0.005773670040071011,
0.02726849354803562,
0.010283778421580791,
0.014489137567579746,
0.007943308912217617,
-0.01033035758882761,
0.010380365885794163,
0.0394442155957222,
-0.005... |
<p>One definition of the chemical potential is the change of internal energy of the system with respect to a particle of the added substance with the system entropy, molar volume, and all other species particle numbers remaining constant.</p>
<p>A thought experiment: Let's suppose I have a completely rigid container w... | g11895 | [
-0.001603329787030816,
-0.00974096916615963,
0.003915834706276655,
-0.005817791912704706,
0.01963047869503498,
-0.01308754738420248,
-0.021322667598724365,
0.04301166534423828,
-0.04301588237285614,
-0.0012655905447900295,
0.026751777157187462,
0.04050478711724281,
0.009318511001765728,
-0... |
<p>We've seen by experiment that the speed of light <em>c</em> appears to be constant for each observer (leading to all well-known consequences of relativity).</p>
<p>I'm wondering if this appearance of constancy of <em>c</em> might be due to the observer's way of measuring it: All observers are bound to compare <em>... | g11896 | [
0.09811149537563324,
0.022540559992194176,
-0.008430310525000095,
-0.017639078199863434,
0.061954621225595474,
0.038302138447761536,
0.08551619946956635,
0.01267282385379076,
-0.02266228199005127,
-0.053926028311252594,
0.029988272115588188,
-0.042049482464790344,
0.032304659485816956,
0.0... |
<p>When we iron our clothes does the mass of the cloth increase, since energy transformation and transfer happens, Einstein's energy mass relation comes to action and causes increase in mass.</p>
<p>Am I right or wrong?</p> | g11897 | [
0.038937538862228394,
0.04498236998915672,
0.020300816744565964,
-0.010429595597088337,
0.0359518900513649,
0.08563399314880371,
0.028089739382267,
0.05928818881511688,
-0.04280802607536316,
-0.022501062601804733,
-0.01726681739091873,
-0.019137660041451454,
0.04387136548757553,
0.02266715... |
<p>One of the wonderful properties of water (as my high school biology teacher would say) is that in its solid form, it is lighter than its liquid form. This means that when temperatures drop below 0 degrees Celsius, the top layer of water on, say, a lake freezes first. This works out pretty well for any fish or other ... | g11898 | [
0.03842151537537575,
-0.012801256030797958,
0.010150458663702011,
-0.026115594431757927,
0.018771344795823097,
0.07241915911436081,
0.01685185544192791,
-0.016063572838902473,
-0.022879883646965027,
-0.03476046770811081,
-0.016185201704502106,
-0.025028690695762634,
-0.01001332513988018,
0... |
<p>If I apply an alternated current to a solenoid and insert into it a smaller solenoid, I could measure the induced EMF (electromotive force) and study how it changes in relation to the frequency of signal generator.</p>
<p>If I increase the frequency, I think that the magnetic fiel increases and so also the EMF incr... | g11899 | [
0.0050157224759459496,
0.054005227982997894,
-0.006461536977440119,
-0.06775666028261185,
0.09216497093439102,
0.02128496766090393,
0.026346631348133087,
0.0013823190238326788,
-0.04980280622839928,
-0.04182235151529312,
-0.09783396124839783,
0.006758399307727814,
-0.01062987931072712,
0.0... |
<p>Ok, so, my simplified understanding of fiber optics is that light is sent down the cable and it rebounds off the sides to end up at its destination. Which got me thinking, if it has to bounce more times (and having a shorter travel between each bounce), does the light (data) take longer to get to the other end of th... | g11900 | [
0.01497749611735344,
0.07481570541858673,
-0.012352398596704006,
-0.0013612230541184545,
0.04860718920826912,
-0.0059338901191949844,
0.03555853292346001,
-0.03496558964252472,
-0.03361004218459129,
-0.05210685357451439,
-0.03187150880694389,
0.011932079680263996,
0.04536983370780945,
-0.0... |
<p>Has the gravitational red shift been proven for electromagnetic waves only or also for a single photon? </p> | g11901 | [
0.017946882173419,
0.0727614164352417,
0.020168913528323174,
0.034168791025877,
0.06784805655479431,
0.07605341821908951,
-0.025064265355467796,
0.004350639414042234,
0.0007920126081444323,
0.0010591569589450955,
0.014936815947294235,
-0.005965263582766056,
0.00006025862239766866,
0.031573... |
<p>I mean what will be the situation inside? All water vaporized, Equilibrium, Temperature-pressure situation.. boiling point increase/decrease?</p>
<p>Thanks for your time.</p> | g11902 | [
-0.020091423764824867,
0.016673618927598,
-0.00430441414937377,
0.06672430783510208,
-0.02067193202674389,
-0.014358393847942352,
-0.030605792999267578,
0.02359488233923912,
0.005896685644984245,
-0.049048908054828644,
-0.06752406060695648,
0.025309968739748,
-0.029996642842888832,
0.01858... |
<p>I've been pondering the precise mechanism of time dilation for the example of a simple pendulum in two different situations:</p>
<ol>
<li><p>The observer and ground are at rest in one frame of reference; the pendulum is moving at high speed with respect to that frame.</p></li>
<li><p>The observer is at rest in one... | g11903 | [
0.048542458564043045,
0.004598634317517281,
0.007487903814762831,
-0.004401413723826408,
0.017667943611741066,
0.03292596712708473,
0.055167634040117264,
-0.003277963725849986,
-0.03297527879476547,
0.018321294337511063,
0.011312947608530521,
-0.02829776145517826,
0.021389378234744072,
-0.... |
<p>I am looking for a model or at best the database of proton fluxes (solar p+) at a energy range of some eV up to 100 keV. I have already found the SOHO database:</p>
<p><a href="http://umtof.umd.edu/pm/" rel="nofollow">http://umtof.umd.edu/pm/</a></p>
<p>But the most energetic p+ was something around 5 ke... | g11904 | [
0.017876271158456802,
0.016676317900419235,
0.009819159284234047,
0.02876647375524044,
-0.04022296518087387,
0.014854089356958866,
-0.03860875591635704,
0.05336552858352661,
-0.011846983805298805,
0.001575578935444355,
0.015137191861867905,
0.02750665880739689,
0.06748630106449127,
-0.0071... |
<p>this might be a "standard trick" for many solid state physicists,
however it's one that I'm not familiar with so maybe you can help me.
Here's the Problem: </p>
<p>Suppose we're given a Hamiltonian of the form
$H=\sum_{k} \epsilon_{k} c^{\dagger}_{k}c_{k} + \sum_{k} U c^{\dagger}_{k+Q} c_{k}$. Here U is some comp... | g11905 | [
0.033813223242759705,
-0.03570936247706413,
-0.020640818402171135,
-0.014928750693798065,
0.026128744706511497,
-0.03976055979728699,
0.058582913130521774,
-0.063850998878479,
-0.006701915059238672,
0.019203340634703636,
-0.006652634125202894,
0.07833138853311539,
-0.01637967675924301,
0.0... |
<p>So our propane tank in the kitchen ran out again today.</p>
<p>Which is more energy efficient, boiling water in a microwave on an electric stove? All things being equal i.e. starting temperature and mass of water.</p>
<p>Not so much about which is faster, but which will cost us less kWh generally.</p>
<p>I reali... | g11906 | [
-0.0017733158310875297,
-0.01067690271884203,
0.02167489007115364,
-0.005567141342908144,
-0.033286917954683304,
-0.022075623273849487,
0.0038079088553786278,
0.0023717351723462343,
-0.022452348843216896,
-0.001066586235538125,
0.0461958684027195,
0.02147272601723671,
0.041699085384607315,
... |
<p>In physics, position as a function of time is generally called <code>d(t)</code> or <code>s(t)</code>. Using "d" is pretty intuitive, however I haven't been able to figure out why "s" is used as well. Is it possibly based on another language?</p> | g11907 | [
0.053370699286460876,
0.013761214911937714,
-0.02621770277619362,
-0.053493931889534,
0.050353873521089554,
-0.0017016504425555468,
0.03780732676386833,
-0.00304489117115736,
-0.011964306235313416,
-0.005908474791795015,
-0.016901008784770966,
-0.024411695078015327,
0.051334578543901443,
-... |
<p>In atomic physics, if a configuration with equivalent electrons in some shell (say Neodymium : $[Xe] 6s^24f^4$) gives same $L = \sum_i l_i$ and $S = \sum_i s_i$ ($i$ denoting individual spin and orbital momentum of the electrons, and in this example $L = 1$ appears twice with $S = 0$) considering the Coulomb intera... | g11908 | [
-0.009618856944143772,
0.05510430410504341,
-0.00974124763160944,
-0.019204577431082726,
0.04629034548997879,
0.0023962121922522783,
-0.012766665779054165,
0.013750073499977589,
0.03187377378344536,
0.005937830079346895,
-0.059041980654001236,
-0.028849037364125252,
0.01661553792655468,
-0... |
<p>can you please help me with that one:</p>
<p>Minimize free energy for a liquid crystal:</p>
<p>$F = \int (K_{11} (div(n))^2 + K_{22} (n*rot(n) + q)^2 + K_{33} (n*rot(n))^2 ) dV$</p>
<p>in the case $n = cos(\alpha)*e_z + sin(\alpha)*e_\phi$ in cylindrical coordinates. $\alpha$ is only dependent of $r$. Goal is to ... | g11909 | [
0.008471577428281307,
0.016872752457857132,
-0.0008398740319535136,
-0.016787312924861908,
0.012777231633663177,
-0.07645703107118607,
0.06158265098929405,
0.0073102740570902824,
-0.04366303235292435,
0.02322443574666977,
-0.02099168486893177,
0.030001141130924225,
-0.05961008742451668,
0.... |
<p>Both my father and my grandfather where drivers, and over time ended up with a wrinklier left hand compared to the right hand, due to sunlight exposure over 40+ years while holding the steering wheel with the left hand. I googled for sunlight exposure through a glass window and I get contradictory answers either sta... | g11910 | [
0.01008990965783596,
-0.020596517249941826,
-0.004608036018908024,
0.041281551122665405,
-0.05134912207722664,
0.006254446692764759,
0.07975317537784576,
0.049073126167058945,
0.04358304664492607,
-0.012600474990904331,
0.055771976709365845,
0.05005776882171631,
0.01778779737651348,
0.0473... |
<p>Reading <a href="http://physics.stackexchange.com/a/94042/21441">this answer</a>, I now wonder: if quarks are confined by $r^2$ potential, could their potential allow infinite motion in higher-dimensional space?</p>
<p>To understand why I thought this might be possible, see what we have with electrostatic potential... | g11911 | [
0.034063003957271576,
0.025877082720398903,
-0.011328180320560932,
-0.016506925225257874,
0.011548003181815147,
0.052020564675331116,
0.005340703763067722,
-0.05240503326058388,
-0.05393872782588005,
0.002984274411574006,
-0.0312325581908226,
0.016742929816246033,
-0.020970644429326057,
-0... |
<p>According to Robert Resnick's book "Introduction to Special Relativity", a line states the following as the definition of an inertial frame of reference: "We define an inertial system as a frame of reference in which the law of inertia - Newton's first law - holds. In such a system, which we may also describe as an ... | g11912 | [
0.012398522347211838,
0.01414746418595314,
0.001738187507726252,
-0.01751060225069523,
0.0431097112596035,
0.018444299697875977,
0.08823800832033157,
0.020665505900979042,
-0.01572064682841301,
-0.021071992814540863,
0.008501737378537655,
-0.05132713541388512,
0.015027298592031002,
-0.0209... |
<p>I have a question that seems natural in Physics and Mathematics mainly in Statistical Mechanics of Equilibrium.</p>
<p>Results that are proven by formal mathematical methods that were already seem intuitive results and experimentally verified when proofs by mathematically rigorous methods were obtained.</p>
<p>In ... | g11913 | [
0.057175688445568085,
0.05405285954475403,
0.020715095102787018,
0.027003813534975052,
-0.022480322048068047,
-0.0017040414968505502,
0.015442450530827045,
0.0028577838093042374,
-0.0008922413107939065,
0.01730591058731079,
-0.00467441463842988,
-0.022825486958026886,
0.10160975903272629,
... |
<p>I have recently started studying physics at school, and my teacher went over the following equation without explaining about it too much:</p>
<p>$$d~=~vt+\frac{1}{2}a t^2.$$</p>
<p>I have wondered, why would this formula actually work? Is there an explanation for this?</p> | g11914 | [
0.025424333289265633,
0.025264281779527664,
-0.019963663071393967,
-0.04806172475218773,
0.050727181136608124,
0.04958615452051163,
0.05332925170660019,
0.028261074796319008,
-0.06145816296339035,
-0.0545494444668293,
-0.009753967635333538,
0.026354486122727394,
0.047155674546957016,
-0.00... |
<p>Where does the factor $\frac{1}{T}$ ($T$ is the string tension) in this Poisson bracket come from?</p>
<p>$$ \{X^{\mu}(\tau,\sigma),\dot{X}^{\nu}(\tau,\sigma')\} ~=~ \frac{1}{T}\delta(\sigma-\sigma')\eta_{\mu\nu}. $$</p>
<p>I think I can see from remembering the definition of a Poisson bracket (for example in cano... | g11915 | [
0.060914888978004456,
0.0037428445648401976,
-0.023665668442845345,
-0.08887200057506561,
0.06461526453495026,
0.026765627786517143,
0.03411726653575897,
0.024793006479740143,
-0.07997889071702957,
0.003628829261288047,
-0.06097642332315445,
0.04398633539676666,
-0.06647942215204239,
-0.04... |
<ol>
<li><p>An operator $A$ is said to be <a href="http://en.wikipedia.org/wiki/Self-adjoint_operator">self-adjoint</a> if $(\chi,A\psi)=(A\chi,\psi)$ for $\psi, \chi \in D_A$ and $D_A=D_{A^\dagger}$. But for the free particle momentum operator $\hat{p}$ these inner products does not exist, however its eigenvalues are ... | g11916 | [
0.017527412623167038,
0.024243630468845367,
-0.015114854089915752,
-0.049939125776290894,
0.07186532020568848,
-0.0639379695057869,
0.026789650321006775,
0.007282891310751438,
-0.018489500507712364,
-0.0070279743522405624,
-0.012908758595585823,
0.011562230065464973,
0.003117592539638281,
... |
<p>What is the physical interpretation of <a href="http://en.wikipedia.org/wiki/Fermi%27s_golden_rule" rel="nofollow">Fermi's golden rule</a>? </p> | g376 | [
-0.004778875503689051,
0.10012808442115784,
-0.034359995275735855,
-0.07258295267820358,
0.05562247335910797,
0.008347571827471256,
0.017556840553879738,
0.008497148752212524,
-0.04166501387953758,
-0.030164498835802078,
-0.003823965322226286,
0.004289311356842518,
0.010952617041766644,
0.... |
<p>I need to prove this relationship:
$$G_{Fredkin} = I \otimes |0\rangle\langle 0| + G_{swap} \otimes |1\rangle\langle 1|$$
with
$$G_{swap} = |00\rangle\langle 00| + |01\rangle\langle 10| + |10\rangle\langle 01| + |11\rangle\langle 11|$$</p>
<p>So I think I need to show that both sides are a linear map on $H \otime... | g11917 | [
-0.01832813397049904,
0.0007363543263636529,
-0.002759430091828108,
-0.05528215691447258,
0.04485045000910759,
-0.034007564187049866,
0.0008343603112734854,
-0.041387367993593216,
0.015741655603051186,
0.03555186837911606,
0.024233806878328323,
-0.0016847491497173905,
0.0017785175004974008,
... |
<p>If you have a wire with current flowing through it, and the current flowing the wrong way (not parallel to the wire) surface charge will buildup, generating a field to force the current to flow the right way.</p>
<p>What's stopping the surface charge from redistributing? After the correct distribution has been set ... | g11918 | [
0.05876781418919563,
0.01576930843293667,
-0.008716034702956676,
0.02488178014755249,
0.06305358558893204,
0.10351146012544632,
0.05834750458598137,
0.011693309992551804,
-0.05963638424873352,
-0.015532688237726688,
-0.05759408697485924,
0.016791315749287605,
-0.008694309741258621,
0.02547... |
<p>Consider a system of two identical quantum particles with spin $s$ and mass $m$. Using center-of-mass coordinates one obtains an equivalent system given by a particle of mass $2m$ and one of mass $m/2$. Can we talk about the $\textit{spin}$ of these two new fictitious particles? What can we say?</p> | g11919 | [
-0.0028929898981004953,
-0.029914528131484985,
0.0009821224957704544,
-0.04535604268312454,
0.0621919110417366,
-0.015198270790278912,
-0.017858857288956642,
-0.02762940712273121,
-0.0031413540709763765,
0.06405392289161682,
-0.009440709836781025,
0.061641570180654526,
0.003954001236706972,
... |
<p>A question related to radiometry:</p>
<p>Irradiance $E$ at a point $x$ can be written as:</p>
<p>$E = \int_\Omega L(x, \omega) cos(\theta) d\omega$</p>
<p>I understand this formula and where it comes from. The equation for radiance can be written as:</p>
<p>$L = {d^2\Phi \over {d\omega dA^\perp cos(\theta)}}$</p... | g11920 | [
0.028661634773015976,
0.003684318857267499,
-0.017779292538762093,
-0.07978449016809464,
0.02382870391011238,
0.04134148359298706,
0.06975074112415314,
0.02553502842783928,
-0.05147293955087662,
0.024500755593180656,
0.006116284988820553,
0.07538031786680222,
0.04411056637763977,
-0.028736... |
<blockquote>
<p><strong>Possible Duplicate:</strong><br>
<a href="http://physics.stackexchange.com/questions/17651/is-it-possible-to-recover-classical-mechanics-from-schrodingers-equation">Is it possible to recover Classical Mechanics from Schrödinger’s equation?</a><br>
<a href="http://physics.stackexchange... | g141 | [
0.027113191783428192,
0.018525145947933197,
0.004999739117920399,
0.06664717197418213,
0.02479088492691517,
0.017773842439055443,
0.02738640457391739,
0.00969014037400484,
0.03856942057609558,
-0.047168243676424026,
0.01740647666156292,
0.009805535897612572,
0.01229473389685154,
0.00662384... |
<p>I have this equation but I have no idea where it came from.</p>
<p>$E_k=k\frac{(q_1q_2)}{r}$</p>
<p>I don't understand especially since I have this other equation:</p>
<p>$E = k\frac{Q_{source}}{r^2}$</p>
<p>And cannot find any relation between the two. Please any helps or suggestions would be useful. Thanks!</p... | g11921 | [
0.05827045440673828,
-0.034522585570812225,
-0.017929406836628914,
-0.011547581292688847,
0.027702881023287773,
0.02956026792526245,
0.0016940797213464975,
0.026087023317813873,
-0.013454892672598362,
-0.0050285495817661285,
-0.038041580468416214,
0.018624886870384216,
0.0794014111161232,
... |
<p>Superconductors are really good at conducting electricity. Should they not reflect light very well too?</p> | g377 | [
-0.03807166591286659,
0.07765768468379974,
0.006069787312299013,
0.007003653794527054,
0.00014955797814764082,
0.04600386321544647,
-0.006712561007589102,
0.023518335074186325,
0.023245511576533318,
-0.04310290515422821,
-0.015132753178477287,
0.0489981546998024,
-0.04938570037484169,
0.02... |
<p>My experience is with atomic spectroscopy of alkali atoms, I've recently been asked by a friend to help with some advice on analyzing molecular spectrophotometry data in the context of molecular biology, </p>
<p>To fit spectroscopic data to extract density in atomic spectroscopy you typically need to know the relat... | g11922 | [
-0.019255314022302628,
0.01950058527290821,
0.013036838732659817,
-0.010323859751224518,
0.03067276068031788,
-0.0294854324311018,
-0.017515767365694046,
0.03939390182495117,
-0.02079598978161812,
0.048259392380714417,
0.02467428147792816,
-0.023670246824622154,
0.01356854010373354,
-0.012... |
<p>I really need some help with a physics problem, and I guess my doubt is more conceptual, than question based. But still, let me pose it to you: </p>
<blockquote>
<p><em>A uniform chain of mass $M$ and length $L$ lies on a rough table, with coefficient of friction $k$. When 1/3rd part of the chain is hanging off t... | g11923 | [
0.03982039541006088,
0.05935753509402275,
-0.005877303425222635,
-0.06918986886739731,
0.04645530506968498,
0.0008662244654260576,
0.03612441569566727,
0.004342366475611925,
-0.07947409898042679,
0.0019390174420550466,
-0.04183629900217056,
-0.01570247858762741,
-0.04231637716293335,
-0.03... |
<p>I am familiar with the notion of irreps. My question refers simply to tensor representations (not tensor products of representations) and how can we decompose them into irreducible parts? For example, a rank 2 tensor is decomposed into an antisymmetric part, a traceless symmetric and its trace. What is the generaliz... | g11924 | [
0.0234366487711668,
0.020099008455872536,
-0.017522946000099182,
-0.027155235409736633,
0.048696406185626984,
-0.01463240571320057,
0.033842381089925766,
0.03131603077054024,
-0.009994637221097946,
0.03582724928855896,
-0.045412227511405945,
0.02907911129295826,
0.00521709444001317,
-0.052... |
<p>Possibility of determining the mass of the water by knowing water volume, water temperature and atmospheric pressure.</p>
<p>I want to know if I can determine the mass of $V=0.01\,m^3$ of water in $T=298\,k$ and $P=1\,atm$.</p>
<p>So what formula should I use?</p> | g11925 | [
0.038571301847696304,
-0.023854319006204605,
0.01610918901860714,
-0.001213089912198484,
-0.013977606780827045,
0.020225225016474724,
0.023001687601208687,
-0.008474001660943031,
-0.021766748279333115,
0.011415181681513786,
0.035982854664325714,
0.01349632441997528,
-0.012159922160208225,
... |
<p>I was reading about alpha decay and why it happens.</p>
<p>The strong force holds protons and neutrons together, but I don't get why does an atom emit helium nucleus when it has too many protons&neutrons? I mean why isn't the strong force holding on to it?</p> | g378 | [
-0.008085889741778374,
0.05876878276467323,
0.009632269851863384,
-0.019195377826690674,
0.05523207411170006,
0.041674986481666565,
-0.043273139744997025,
0.09752298146486282,
-0.007789143361151218,
-0.10301893949508667,
0.026984892785549164,
0.01261688582599163,
-0.011026437394320965,
0.0... |
<p>Here is a following problem I encountered when chatting about physics with my friend:</p>
<p>Let us imagine a classical example of ordered state of matter in thermodynamic sense: let's take a cylinder filled with air in normal pressure. Now let's make order in the chaotic movement of air particles and arrange their... | g11926 | [
0.015505759976804256,
0.015467323362827301,
0.00934109278023243,
0.008683486841619015,
0.006964314263314009,
-0.04777593910694122,
-0.005374481435865164,
0.033662356436252594,
-0.09156127274036407,
-0.009474522434175014,
0.03341090679168701,
-0.014697735197842121,
-0.013089216314256191,
-0... |
<p>I have been racking my brains over the differences between laser spectral width and something called the linewidth. The linewidth was written about in detail by <a href="http://ieeexplore.ieee.org/xpl/freeabs_all.jsp?arnumber=1071522" rel="nofollow">Henry in 1982</a>. The spectral width is the width at -20dB down ... | g11927 | [
-0.005178769584745169,
-0.029941260814666748,
-0.0035758893936872482,
-0.021159449592232704,
0.02468550018966198,
-0.0032867996487766504,
-0.006448393687605858,
0.029739389196038246,
-0.024229886010289192,
-0.07360830157995224,
0.04572119563817978,
-0.007712598890066147,
0.00558684766292572,... |
<p>I don't know the <strong>EXACT</strong> measurements, but I can closely guess that the bumper is about 18 inches from the ground, and the engine is in the front, yes(the engine is about 20 inches from the front bumper inside the hood, and about 23 inches centered between the hood on both sides). I don't know what th... | g11928 | [
0.026086829602718353,
0.023361362516880035,
-0.008021563291549683,
0.02917308546602726,
0.03438521921634674,
-0.058692362159490585,
0.040777429938316345,
0.044947270303964615,
-0.07676174491643906,
0.029474910348653793,
-0.004506886005401611,
-0.04332183301448822,
-0.004469999577850103,
0.... |
<p>People frequently speak about an atomic system decaying from an excited state to the ground state. However, both the ground states and the excited states are defined as eigenstates of the Hamiltonian operator for the system. This implies then that up to a time-dependent complex phase, they are invariant under evolut... | g11929 | [
-0.0020279271993786097,
0.04280081391334534,
-0.002968523884192109,
-0.031090332195162773,
0.03410118445754051,
0.028129644691944122,
0.045029595494270325,
0.06832271814346313,
0.052199456840753555,
-0.031745314598083496,
-0.04515856131911278,
0.0005296592134982347,
0.061745401471853256,
0... |
<p>Firstly, I'm aware that Hawking radiation can be derived in the "normal" way using the Bogoliubov transformation. However, I was intrigued by the heuristic explanation in terms of tunneling. The story goes that a virtual particle-antiparticle pair arises just outside the horizon. The negative energy partner tunne... | g11930 | [
0.07814805954694748,
0.024488775059580803,
-0.008742021396756172,
0.026119675487279892,
0.04107125848531723,
0.04098844900727272,
-0.015328860841691494,
0.08321502804756165,
-0.005860556848347187,
0.0161968395113945,
0.031595733016729355,
0.032603953033685684,
0.022533150389790535,
0.03504... |
<p>I think that charging symmetry assumes antiparticle presence, which has an opposite charge sign . And what symmetry assumes existence of an antiparticle at a neutral particle</p> | g11931 | [
0.03264056518673897,
0.03984581679105759,
0.005138373468071222,
-0.006736605428159237,
0.10340064018964767,
0.04965118691325188,
-0.011866546235978603,
0.0043674916960299015,
-0.01766609586775303,
-0.01799108274281025,
-0.015723878517746925,
0.014086563140153885,
-0.030277905985713005,
0.0... |
<p>Are there any materials that are mostly "transparent" to x-rays? Such as glass would be to the visible spectrum? </p>
<p>What about materials or surfaces that reflect x-rays? Does most metal reflect x-rays?</p>
<p>What about materials that are mostly opaque? I know lead can absorb x-rays, but is there anything els... | g11932 | [
0.06050819531083107,
0.01903792843222618,
0.006271934602409601,
0.008355519734323025,
0.008467407897114754,
0.05943116173148155,
-0.07259508967399597,
0.024387307465076447,
0.059298157691955566,
-0.00848664902150631,
0.10323716700077057,
0.06786534190177917,
0.02672807313501835,
-0.0440163... |
<p><a href="http://en.wikipedia.org/wiki/Active_noise_control">Active noise cancelling</a> reduces unwanted sound by sending the inverted phase of the original phase:
<img src="http://i.stack.imgur.com/0jSp8.png" alt="Active noise cancelling"></p>
<p>(Source: <a href="http://upload.wikimedia.org/wikipedia/commons/thum... | g107 | [
0.07167597115039825,
-0.039946697652339935,
0.008484935387969017,
0.01118573546409607,
0.030906474217772484,
0.005543464329093695,
-0.009981679730117321,
0.06194024905562401,
-0.04419670253992081,
0.0039134458638727665,
-0.009264341555535793,
0.008340650238096714,
-0.0016234947834163904,
0... |
<p>Why are the poles colder than the rest ofthe planet?Is the gravity stronger making molecules spin slower?How does gravity affect heat and hydrogen bonds? And what affects gravity?A little off topic but Also, if you have alot of copper in your blood versus iron,does it affect your temperature?How does oxygen affect t... | g11933 | [
0.0396958589553833,
0.040917206555604935,
-0.023269597440958023,
0.04157119616866112,
0.04485119879245758,
0.024781832471489906,
0.014467963017523289,
0.024722956120967865,
-0.03317106515169144,
-0.018185339868068695,
-0.004333062097430229,
-0.012751471251249313,
-0.002412572270259261,
0.0... |
<p>Assume I have a 1m3 tank of air at 100 psi, they are going to release to a 1m3 tank which has air at 5 psi. There is a meter long pipe connect between two tanks.</p>
<p>How to calculate the flow speed ratio if the pipe is 1" diameter & connection at 5psi tank is also 1" and the pipe is 1" diameter and the conn... | g11934 | [
0.013066054321825504,
-0.020451193675398827,
0.012068388052284718,
0.004855959210544825,
-0.0018877482507377863,
-0.021177450194954872,
0.05794036388397217,
-0.021818198263645172,
-0.06340201944112778,
0.0004476143221836537,
0.03235632926225662,
0.03391806408762932,
-0.021711764857172966,
... |
<p>Can I use Poiseuille's equation?</p>
<p>Also
If I have a vacuum pump which says that its performance is 30 cubic feet per minutes and I have two pipes (one is radius R1 and L1, the other one is 2*R1 and 0.5*L1), will the vacuum do the same 30 CFM?</p> | g11935 | [
0.02994162030518055,
0.023907553404569626,
0.0006713222828693688,
0.01277062576264143,
0.035454388707876205,
0.03962300717830658,
0.008328410796821117,
-0.010370234958827496,
-0.07738050818443298,
-0.00798566173762083,
-0.01768239587545395,
-0.01015589851886034,
-0.0371369831264019,
0.0190... |
<p>If my understanding is correct, neither reversible nor adiabatic processes are necessarily isentropic.</p>
<p>But are reversible adiabatic processes always isentropic?</p> | g11936 | [
0.06976527720689774,
0.009805068373680115,
0.03029114566743374,
0.018595319241285324,
0.0737648531794548,
-0.007890189066529274,
-0.002005981747061014,
0.0472620464861393,
0.02864917553961277,
0.0019511773716658354,
0.016201168298721313,
0.06373972445726395,
-0.03929236903786659,
-0.027917... |
<p>Is it possible to measure the phase of a quantum field or quantum particle, as an observable?</p> | g11937 | [
-0.036662615835666656,
0.019984103739261627,
0.007950830273330212,
-0.07513593882322311,
0.07933640480041504,
-0.0186783280223608,
-0.07990111410617828,
0.022063473239541054,
0.0016575406771153212,
-0.015193454921245575,
-0.01688062958419323,
0.0047345091588795185,
-0.04723888263106346,
0.... |
<p>I have two related questions on the representation of the momentum operator in the position basis.</p>
<p>The action of the momentum operator on a wave function is to derive it:</p>
<p>$$\hat{p} \psi(x)=-i\hbar\frac{\partial\psi(x)}{\partial x}$$</p>
<p><strong>(1)</strong> Is it ok to conclude from this that:</p... | g11938 | [
0.028011471033096313,
-0.006787827238440514,
-0.011393479071557522,
-0.01033223420381546,
0.08575605601072311,
0.011025488376617432,
0.06271989643573761,
0.03352168947458267,
-0.024921350181102753,
-0.010410331189632416,
-0.033541686832904816,
-0.029171200469136238,
-0.04961850121617317,
-... |
<p>Does Gauss law holds for any closed surface or it only holds for only <a href="http://en.wikipedia.org/wiki/Gaussian_surface" rel="nofollow">Gaussian surface</a>.</p>
<p>Are every closed surface a Gaussian surface?</p> | g11939 | [
0.014663249254226685,
-0.0417117215692997,
0.017396146431565285,
0.015008733607828617,
0.04670985788106918,
0.07660378515720367,
-0.00022074507432989776,
0.005542367231100798,
-0.003035526489838958,
-0.07324032485485077,
-0.03150426596403122,
0.02645070105791092,
-0.004385349340736866,
0.0... |
Subsets and Splits
No community queries yet
The top public SQL queries from the community will appear here once available.