publicationDate stringlengths 1 2.79k | title stringlengths 1 36.5k ⌀ | abstract stringlengths 1 37.3k ⌀ | id stringlengths 9 47 |
|---|---|---|---|
2002-12-30 | Dark propagation modes in optical lattices | We examine the stimulated light scattering onto the propagation modes of a
dissipative optical lattice. We show that two different pump-probe
configurations may lead to the excitation, via different mechanisms, of the
same mode. We found that in one configuration the scattering on the propagation
mode results in a reso... | 0212157v1 |
2003-09-29 | Phase-control of directed diffusion in a symmetric optical lattice | We demonstrate the phenomenon of directed diffusion in a symmetric periodic
potential. This has been realized with cold atoms in a one-dimensional
dissipative optical lattice. The stochastic process of optical pumping leads to
a diffusive dynamics of the atoms through the periodic structure, while a
zero-mean force whi... | 0309208v1 |
2003-09-29 | Synchronization of Hamiltonian motion and dissipative effects in optical lattices: Evidence for a stochastic resonance | We theoretically study the influence of the noise strength on the excitation
of the Brillouin propagation modes in a dissipative optical lattice. We show
that the excitation has a resonant behavior for a specific amount of noise
corresponding to the precise synchronization of the Hamiltonian motion on the
optical poten... | 0309210v1 |
2006-06-23 | Playing Quantum Physics Jeopardy with zero-energy eigenstates | We describe an example of an exact, quantitative Jeopardy-type quantum
mechanics problem. This problem type is based on the conditions in
one-dimensional quantum systems that allow an energy eigenstate for the
infinite square well to have zero curvature and zero energy when suitable Dirac
delta functions are added. Thi... | 0606196v1 |
2006-10-18 | Subsystem Codes | We investigate various aspects of operator quantum error-correcting codes or,
as we prefer to call them, subsystem codes. We give various methods to derive
subsystem codes from classical codes. We give a proof for the existence of
subsystem codes using a counting argument similar to the quantum
Gilbert-Varshamov bound.... | 0610153v1 |
2007-05-14 | The dynamical response to the node defect in thermally activated remagnetization of magnetic dot array | The influence of nonmagnetic central node defect on dynamical properties of
regular square-shaped 5 x 5 segment of magnetic dot array under the thermal
activation is investigated via computer simulations. Using stochastic
Landau-Lifshitz-Gilbert equation we simulate hysteresis and relaxation
processes. The remarkable q... | 0705.1889v1 |
2007-05-18 | Steady-state conduction in self-similar billiards | The self-similar Lorentz billiard channel is a spatially extended
deterministic dynamical system which consists of an infinite one-dimensional
sequence of cells whose sizes increase monotonically according to their
indices. This special geometry induces a nonequilibrium stationary state with
particles flowing steadily ... | 0705.2758v1 |
2007-06-04 | Generation of microwave radiation in planar spin-transfer devices | Current induced precession states in spin-transfer devices are studied in the
case of large easy plane anisotropy (present in most experimental setups). It
is shown that the effective one-dimensional planar description provides a
simple qualitative understanding of the emergence and evolution of such states.
Switching ... | 0706.0529v1 |
2007-12-26 | Mass and angular-momentum inequalities for axi-symmetric initial data sets. II. Angular-momentum | We extend the validity of Dain's angular-momentum inequality to maximal,
asymptotically flat, initial data sets on a simply connected manifold with
several asymptotically flat ends which are invariant under a U(1) action and
which admit a twist potential. | 0712.4064v2 |
2008-01-28 | TER: A Robot for Remote Ultrasonic Examination: Experimental Evaluations | This chapter:
o Motivates the clinical use of robotic tele-echography
o Introduces the TER system
o Describes technical and clinical evaluations performed with TER | 0801.4355v1 |
2008-03-14 | Spin-torque shot noise in magnetic tunnel junctions | Spin polarized current may transfer angular momentum to a ferromagnet,
resulting in a spin-torque phenomenon. At the same time the shot noise,
associated with the current, leads to a non-equilibrium stochastic force acting
on the ferromagnet. We derive stochastic version of Landau-Lifshitz-Gilbert
equation for a magnet... | 0803.2101v1 |
2008-04-07 | Paired Orbitals for Different Spins equations | Eigenvalue-type equations for Lowdin-Amos-Hall spin-paired (corresponding)
orbitals are developed to provide an alternative to the standard spin-polarized
Hartree-Fock or Kohn-Sham equations. Obtained equations are non-canonical
unrestricted Hartree-Fock-type equations in which non-canonical orbitals are
fixed to be bi... | 0804.0967v1 |
2008-04-26 | Spin-torque oscillator based on tilted magnetization of the fixed layer | The spin torque oscillator (STO), where the magnetization of the fixed layer
is tilted out of the film plane, is capable of strong microwave signal
generation in zero magnetic field. Through numerical simulations of the
Landau-Lifshitz-Gilbert-Slonczewski equations, within a macro-spin
approximation, we study the micro... | 0804.4213v1 |
2008-07-11 | Superconductivity up to 29 K in SrFe2As2 and BaFe2As2 at high pressures | We report the discovery of superconductivity at high pressure in SrFe2As2 and
BaFe2As2. The superconducting transition temperatures are up to 27 K in
SrFe2As2 and 29 K in BaFe2As2, making these the highest pressure-induced
superconducting materials discovered thus far. | 0807.1896v2 |
2008-07-14 | An Adaptive Entanglement Distillation Scheme Using Quantum Low Density Parity Check Codes | Quantum low density parity check (QLDPC) codes are useful primitives for
quantum information processing because they can be encoded and decoded
efficiently. Besides, the error correcting capability of a few QLDPC codes
exceeds the quantum Gilbert-Varshamov bound. Here, we report a numerical
performance analysis of an a... | 0807.2122v1 |
2008-07-16 | Analytical solution of the equation of motion for a rigid domain wall in a magnetic material with perpendicular anisotropy | This paper reports the solution of the equation of motion for a domain wall
in a magnetic material which exhibits high magneto-crystalline anisotropy.
Starting from the Landau-Lifschitz-Gilbert equation for field-induced motion,
we solve the equation to give an analytical expression, which specifies the
domain wall pos... | 0807.2604v3 |
2008-07-16 | A graphical extension for the Windows version of the Parallel Finite Element Micromagnetics Package (MagParExt) | In the current paper we present a graphical user interface useful for
settings input parameter of the Windows precompiled binaries for the Parallel
Finite Element Micromagnetics Package (MagPar). The Package is used for
magnetization dynamics analysis on a base of the Landau-Lifshitz-Gilbert (LLG)
equation. In an avail... | 0807.2655v1 |
2008-08-17 | Attempt frequency of magnetization in nanomagnets with thin-film geometry | Solving the stochastic Landau-Lifshitz-Gilbert equation numerically, we
investigate the effect of the potential landscape on the attempt frequency of
magnetization in nanomagnets with the thin-film geometry. Numerical estimates
of the attempt frequency are analyzed in comparison with theoretical
predictions from the Fo... | 0808.2281v1 |
2008-08-30 | Path integral study of the role of correlation in exchange coupling of spins in double quantum dots and optical lattices | We explore exchange coupling of a pair of spins in a double dot and in an
optical lattice. Our algorithm uses the frequency of exchanges in a bosonic
path integral, evaluated with Monte Carlo. This algorithm is simple enough to
be a "black box" calculator, yet gives insights into the role of correlation
through two-par... | 0809.0038v1 |
2008-09-16 | Stochastic dynamics of magnetization in a ferromagnetic nanoparticle out of equilibrium | We consider a small metallic particle (quantum dot) where ferromagnetism
arises as a consequence of Stoner instability. When the particle is connected
to electrodes, exchange of electrons between the particle and the electrodes
leads to a temperature- and bias-driven Brownian motion of the direction of the
particle mag... | 0809.2611v1 |
2008-12-09 | On densest packings of equal balls of $\rb^{n}$ and Marcinkiewicz spaces | We investigate, by "a la Marcinkiewicz" techniques applied to the
(asymptotic) density function, how dense systems of equal spheres of $\rb^{n},
n \geq 1,$ can be partitioned at infinity in order to allow the computation of
their density as a true limit and not a limsup. The density of a packing of
equal balls is the n... | 0812.1720v1 |
2009-01-26 | Bioprotectant glassforming solutions confined in porous silicon nanocapillaries | Glycerol and trehalose-glycerol binary solutions are glass-forming liquids
with remarkable bioprotectant properties. In this paper, we address the effects
of confining of these solutions in straight channels of diameter D=8 nm formed
by porous silicon. Neutron diffraction and incoherent quasielastic neutron
scattering ... | 0901.3994v1 |
2009-02-12 | Computing equations for residually free groups | We show that there is no algorithm deciding whether the maximal residually
free quotient of a given finitely presented group is finitely presentable or
not.
Given a finitely generated subgroup G of a finite product of limit groups, we
discuss the possibility of finding an explicit set of defining equations (i.e.
of e... | 0902.2119v2 |
2009-03-06 | Simulation of current-induced microwave oscillation in geometrically confined domain wall | We studied magnetization dynamics of a geometrically confined domain wall
under dc current by solving simultaneously the Landau-Lifshitz-Gilbert equation
and diffusion equation for spin accumulation. We showed that the oscillation
motion of the domain wall is driven by the spin-transfer torque and the dc
current is con... | 0903.1151v1 |
2009-04-05 | Projective Space Codes for the Injection Metric | In the context of error control in random linear network coding, it is useful
to construct codes that comprise well-separated collections of subspaces of a
vector space over a finite field. In this paper, the metric used is the
so-called "injection distance", introduced by Silva and Kschischang. A
Gilbert-Varshamov bou... | 0904.0813v2 |
2009-05-28 | Hamilton cycles in random geometric graphs | We prove that, in the Gilbert model for a random geometric graph, almost
every graph becomes Hamiltonian exactly when it first becomes 2-connected. This
answers a question of Penrose. We also show that in the k-nearest neighbor
model, there is a constant \kappa\ such that almost every \kappa-connected
graph has a Hamil... | 0905.4650v2 |
2009-06-25 | Nonlinear Schroedinger-Poisson Theory for Quantum-Dot Helium | We use a nonlinear Schroedinger-Poisson equation to describe two interacting
electrons with opposite spins confined in a parabolic potential, a quantum dot.
We propose an effective form of the Poisson equation taking into account the
dimensional mismatch of the two-dimensional electronic system and the
three-dimensiona... | 0906.4650v1 |
2009-06-29 | Performance of Magnetic Quantum Cellular Automata and Limitations due to Thermal Noise | Operation parameters of magnetic quantum cellular automata are evaluated for
the purposes of reliable logic operation. The dynamics of the nanomagnets is
simulated via the Landau-Lifshitz-Gilbert equations with a stochastic magnetic
field corresponding to thermal fluctuations. It is found that in the macrospin
approxim... | 0906.5172v1 |
2009-09-15 | Critical current density for spin transfer torque switching with composite free layer structure | Critical current density of composite free layer (CFL) in magnetic tunneling
junction is investigated. CFL consists of two exchange coupled ferromagnetic
layers, where the coupling is parallel or anti-parallel. Instability condition
of the CFL under the spin transfer torque, which is related with critical
current densi... | 0909.2711v1 |
2009-09-25 | Tunable steady-state domain wall oscillator with perpendicular magnetic anisotropy | We theoretically study domain wall oscillations upon the injection of a dc
current through a geometrically constrained wire with perpendicular magnetic
anisotropy. The oscillation frequency spectrum can be tuned by the injected
current density, but additionally by the application of an external magnetic
field independe... | 0909.4733v1 |
2009-10-13 | Dipolar field effect on microwave oscillation in a domain wall spin-valve | We examined dipolar field effects on the microwave generation in the domain
wall spin-valve by solving simultaneously the Landau-Lifshitz-Gilbert and
Zhang-Levy-Fert diffusion equations. By numerically analyzing dipolar field
dependence, we showed that the microwave generation needs the dipole-dipole
interaction for a ... | 0910.2280v1 |
2009-10-30 | Dissipative dynamics of magnetic solitons in metals | Soliton dynamics in spin-textured metals generate electrical currents, which
produce backaction through spin torques. We modify the Landau-Lifshitz-Gilbert
equation and the corresponding solitonic equations of motion to include such
higher-order texture effects. We also find a quasistatic equation for the
induced elect... | 0910.5912v2 |
2009-11-16 | JSJ decompositions: definitions, existence, uniqueness. I: The JSJ deformation space | This paper and its companion arXiv:1002.4564 have been replaced by
arXiv:1602.05139.
We give a general simple definition of JSJ decompositions by means of a
universal maximality property. The JSJ decomposition should not be viewed as a
tree (which is not uniquely defined) but as a canonical deformation space of
trees... | 0911.3173v3 |
2010-02-15 | Domain wall motion in ferromagnetic nanowires driven by arbitrary time-dependent fields: An exact result | We address the dynamics of magnetic domain walls in ferromagnetic nanowires
under the influence of external time-dependent magnetic fields. We report a new
exact spatiotemporal solution of the Landau-Lifshitz-Gilbert equation for the
case of soft ferromagnetic wires and nanostructures with uniaxial anisotropy.
The solu... | 1002.2913v1 |
2010-05-24 | SN2010U -- a Luminous Nova in NGC 4214 | The luminosity, light curve, post--maximum spectrum, and lack of a progenitor
on deep pre-outburst images suggest that SN 2010U was a luminous, fast nova.
Its outburst magnitude is consistent with that for a fast nova using the
Maximum Magnitude-Rate of Decline relationship for classical novae. | 1005.4356v1 |
2010-06-11 | Highly Parallel Sparse Matrix-Matrix Multiplication | Generalized sparse matrix-matrix multiplication is a key primitive for many
high performance graph algorithms as well as some linear solvers such as
multigrid. We present the first parallel algorithms that achieve increasing
speedups for an unbounded number of processors. Our algorithms are based on
two-dimensional blo... | 1006.2183v1 |
2010-06-24 | Boundary regularity for minimizers of the micromagnetic energy functional | Motivated by the construction of time-periodic solutions for the
three-dimensional Landau-Lifshitz-Gilbert equation in the case of soft and
small ferromagnetic particles, we investigate the regularity properties of
minimizers of the micromagnetic energy functional at the boundary. In
particular, we show that minimizers... | 1006.4766v1 |
2010-06-24 | Time-periodic Néel wall motions | In thin ferromagnetic films, the predominance of the magnetic shape
anisotropy leads to in-plane magnetizations. The simplest domain wall in this
geometry is the one-dimensional Neel wall that connects two magnetizations of
opposite sign by a planar 180 degree rotation. In this paper, we perturb the
static Neel wall pr... | 1006.4768v1 |
2010-06-30 | Supercurrent-Induced Magnetization Dynamics | We investigate supercurrent-induced magnetization dynamics in a Josephson
junction with two misaligned ferromagnetic layers, and demonstrate a variety of
effects by solving numerically the Landau-Lifshitz-Gilbert equation. In
particular, we demonstrate the possibility to obtain supercurrent-induced
magnetization switch... | 1007.0004v1 |
2010-07-09 | Polarization and magnetization dynamics of a field-driven multiferroic structure | We consider a multiferroic chain with a linear magnetoelectric coupling
induced by the electrostatic screening at the ferroelectric/ferromagnet
interface. We study theoretically the dynamic ferroelectric and magnetic
response to external magnetic and electric fields by utilizing an approach
based on coupled Landau- Kha... | 1007.1543v1 |
2010-07-11 | Factorization of banded permutations | We consider the factorization of permutations into bandwidth 1 permutations,
which are products of mutually nonadjacent simple transpositions. We exhibit an
upper bound on the minimal number of such factors and thus prove a conjecture
of Gilbert Strang: a banded permutation of bandwidth $w$ can be represented as
the pr... | 1007.1760v2 |
2010-07-14 | Nonlinear interference in a mean-field quantum model | Using similar nonlinear stationary mean-field models for Bose-Einstein
Condensation of cold atoms and interacting electrons in a Quantum Dot, we
propose to describe the original many-particle ground state as a one-particle
statistical mixed state of the nonlinear eigenstates whose weights are provided
by the eigenstate... | 1007.2408v1 |
2011-01-17 | Steiner Ratio for Manifolds | The Steiner ratio characterizes the greatest possible deviation of the length
of a minimal spanning tree from the length of the minimal Steiner tree. In this
paper, estimates of the Steiner ratio on Riemannian manifolds are obtained. As
a corollary, the Steiner ratio for flat tori, flat Klein bottles, and
projective pl... | 1101.3144v1 |
2011-02-04 | Current-induced dynamics of composite free layer with antiferromagnetic interlayer exchange coupling | Current-induced dynamics in spin valves including composite free layer with
antiferromagnetic interlayer exchange coupling is studied theoretically within
the diffusive transport regime. We show that current-induced dynamics of a
synthetic antiferromagnet is significantly different from dynamics of a
synthetic ferrimag... | 1102.1028v2 |
2011-04-01 | Spin waves cause non-linear friction | Energy dissipation is studied for a hard magnetic tip that scans a soft
magnetic substrate. The dynamics of the atomic moments are simulated by solving
the Landau-Lifshitz-Gilbert (LLG) equation numerically. The local energy
currents are analysed for the case of a Heisenberg spin chain taken as
substrate. This leads to... | 1104.0197v2 |
2011-05-31 | Upper and Lower Bounds on the Minimum Distance of Expander Codes | The minimum distance of expander codes over GF(q) is studied. A new upper
bound on the minimum distance of expander codes is derived. The bound is shown
to lie under the Varshamov-Gilbert (VG) bound while q >= 32. Lower bounds on
the minimum distance of some families of expander codes are obtained. A lower
bound on the... | 1105.6224v1 |
2011-06-28 | Stability of precessing domain walls in ferromagnetic nanowires | We show that recently reported precessing solution of Landau-Lifshitz-Gilbert
equations in ferromagnetic nanowires is stable under small perturbations of
initial data, applied field and anisotropy constant. Linear stability is
established analytically, while nonlinear stability is verified numerically. | 1106.5808v2 |
2011-07-01 | Current induced magnetization reversal on the surface of a topological insulator | We study dynamics of the magnetization coupled to the surface Dirac fermions
of a three di- mensional topological insulator. By solving the
Landau-Lifshitz-Gilbert equation in the presence of charge current, we find
current induced magnetization dynamics and discuss the possibility of mag-
netization reversal. The torq... | 1107.0116v1 |
2011-08-05 | Thermoelectric detection of ferromagnetic resonance of a nanoscale ferromagnet | We present thermoelectric measurements of the heat dissipated due to
ferromagnetic resonance of a Permalloy strip. A microwave magnetic field,
produced by an on-chip coplanar strip waveguide, is used to drive the
magnetization precession. The generated heat is detected via Seebeck
measurements on a thermocouple connect... | 1108.1286v1 |
2011-08-31 | Effects of Fermion Flavor on Exciton Condensation in Double Layer Systems | We use fermionic path integral quantum Monte Carlo to study the effects of
fermion flavor on the physical properties of dipolar exciton condensates in
double layer systems. We find that by including spin in the system weakens the
effective interlayer interaction strength, yet this has very little effect on
the Kosterli... | 1108.6107v1 |
2011-09-30 | An ultrafast image recovery and recognition system implemented with nanomagnets possessing biaxial magnetocrystalline anisotropy | A circular magnetic disk with biaxial magnetocrystalline anisotropy has four
stable magnetization states which can be used to encode a pixel's shade in a
black/gray/white image. By solving the Landau-Lifshitz- Gilbert equation, we
show that if moderate noise deflects the magnetization slightly from a stable
state, it a... | 1109.6932v1 |
2011-11-10 | Magnonic band structure of a two-dimensional magnetic superlattice | The frequencies and linewidths of spin waves in a two-dimensional periodic
superlattice of magnetic materials are found, using the Landau-Lifshitz-Gilbert
equations. The form of the exchange field from a surface-torque-free boundary
between magnetic materials is derived, and magnetic-material combinations are
identifie... | 1111.2506v1 |
2011-11-29 | Supercurrent induced domain wall motion | We study the dynamics of a magnetic domain wall, inserted in, or juxtaposed
to, a conventional superconductor, via the passage of a spin polarized current
through a FSF junction. Solving the Landau-Lifshitz-Gilbert equation of motion
for the magnetic moments we calculate the velocity of the domain wall and
compare it w... | 1111.6751v1 |
2011-12-02 | The Main Diagonal of a Permutation Matrix | By counting 1's in the "right half" of $2w$ consecutive rows, we locate the
main diagonal of any doubly infinite permutation matrix with bandwidth $w$.
Then the matrix can be correctly centered and factored into block-diagonal
permutation matrices. Part II of the paper discusses the same questions for the
much larger c... | 1112.0582v2 |
2011-12-11 | Stability of the Greedy Algorithm on the Circle | We consider a single-server system with service stations in each point of the
circle. Customers arrive after exponential times at uniformly-distributed
locations. The server moves at finite speed and adopts a greedy routing
mechanism. It was conjectured by Coffman and Gilbert in~1987 that the service
rate exceeding the... | 1112.2389v3 |
2011-12-12 | Riffle shuffles with biased cuts | The well-known Gilbert-Shannon-Reeds model for riffle shuffles assumes that
the cards are initially cut 'about in half' and then riffled together. We
analyze a natural variant where the initial cut is biased. Extending results of
Fulman (1998), we show a sharp cutoff in separation and L-infinity distances.
This analysi... | 1112.2650v1 |
2011-12-15 | Solutions of the Fully Compressible Semi-Geostrophic System | The fully compressible semi-geostrophic system is widely used in the
modelling of large-scale atmospheric flows. In this paper, we prove rigorously
the existence of weak Lagrangian solutions of this system, formulated in the
original physical coordinates. In addition, we provide an alternative proof of
the earlier resu... | 1112.3553v2 |
2012-01-23 | Micromagnetic Simulations for Spin Transfer Torque in Magnetic Multilayers | We investigate the spin transfer torque (STT) in the magnetic multilayer
structures with micromagnetic simulations. We implement the STT contribution
for the magnetic multilayer structures in addition to the
Landau-Lifshitz-Gilbert (LLG) micromagnetic simulators. Not only the Sloncewski
STT term, the zero, first, and s... | 1201.4707v1 |
2012-01-26 | Pseudospin Transfer Torques in Semiconductor Electron Bilayers | We use self-consistent quantum transport theory to investigate the influence
of electron-electron interactions on interlayer transport in semiconductor
electron bilayers in the absence of an external magnetic field. We conclude
that, even though spontaneous pseudospin order does not occur at zero field,
interaction-enh... | 1201.5569v2 |
2012-03-03 | Skyrmion Generation by Current | Skyrmions, once a hypothesized field-theoretical object believed to describe
the nature of elementary particles, became common sightings in recent years
among several non-centrosymmetric metallic ferromagnets. For more practical
applications of Skyrmionic matter as carriers of information, thus realizing
the prospect o... | 1203.0638v1 |
2012-04-25 | Numerical Study on Spin Torque Switching in Thermally Activated Region | We studied the spin torque switching of the single free layer in the
thermally activated region by numerically solving the Landau-Lifshitz-Gilbert
equation. We found that the temperature dependence of the switching time of the
in-plane magnetized system is nonlinear, which means $b \neq 1$. Here, $b$ is
the exponent of... | 1204.5596v2 |
2012-07-13 | Theory of current-driven motion of Skyrmions and spirals in helical magnets | We study theoretically the dynamics of the spin textures, i.e., Skyrmion
crystal (SkX) and spiral structure (SS), in two-dimensional helical magnets
under external current. By numerically solving the Landau-Lifshitz-Gilbert
equation, it is found that (i) the critical current density of the motion is
much lower for SkX ... | 1207.3224v1 |
2012-07-19 | Solar Orbiter: Exploring the Sun-heliosphere connection | The heliosphere represents a uniquely accessible domain of space, where
fundamental physical processes common to solar, astrophysical and laboratory
plasmas can be studied under conditions impossible to reproduce on Earth and
unfeasible to observe from astronomical distances. Solar Orbiter, the first
mission of ESA's C... | 1207.4579v2 |
2012-07-19 | Harnessing the modulation instability spectrum in optical fibers with a periodic dispersion landscape | We report the experimental demonstration of modulation instability process
assisted by a dispersion grating in an optical fiber. A simple analytical model
is developed to further analyze and explain the complex dynamics of this
process, showing that each of the multiple spectral components grows thanks to
a quasi phase... | 1207.4667v1 |
2012-08-11 | Lexicodes over Rings | In this paper, we consider the construction of linear lexicodes over finite
chain rings by using a $B$-ordering over these rings and a selection criterion.
% and a greedy Algorithm. As examples we give lexicodes over $\mathbb{Z}_4$ and
$\mathbb{F}_2+u\mathbb{F}_2$. %First, greedy algorithms are presented to
construct %... | 1208.2361v2 |
2012-09-07 | Self-sustained current oscillations in spin-blockaded quantum dots | Self-sustained current oscillation observed in spin-blockaded double quantum
dots is explained as a consequence of periodic motion of dynamically polarized
nuclear spins (along a limit cycle) in the spin-blockaded regime under an
external magnetic field and a spin-transfer torque. It is shown, based on the
Landau-Lifsh... | 1209.1548v1 |
2012-10-04 | All Spin Nano-magnetic State Elements | We propose an all spin state element to enable all spin state machines using
spin currents and nanomagnets. We demonstrate via numerical simulations the
operation of a state element a critical building block for synchronous,
sequential logic computation. The numerical models encompass
Landau-Lifshitz-Gilbert (LLG) nano... | 1210.1613v1 |
2012-11-02 | Effect of Spin Torque on Magnetization Switching Speed Having Nonuniform Spin Distribution | We study the influence of the spin torque, which depends on the space and
time derivative of magnetization, on magnetization reversal time in a
ferromagnetic fine particle. The spin torque operates to dissipate the angular
momentum of the magnetization precession, and the torque increases in a spin
vortex structure. We... | 1211.0360v1 |
2013-01-14 | magnum.fe: A micromagnetic finite-element simulation code based on FEniCS | We have developed a finite-element micromagnetic simulation code based on the
FEniCS package called magnum.fe. Here we describe the numerical methods that
are applied as well as their implementation with FEniCS. We apply a
transformation method for the solution of the demagnetization-field problem. A
semi-implicit weak... | 1301.3061v2 |
2013-02-04 | Control of dissipation in superconducting films by magnetic stray fields | Hybrid superconducting/magnetic nanostructures on Si substrates have been
built with identical physical dimensions but different magnetic configurations.
By constructing arrays based on Co-dots with in-plane, out-of-plane, and vortex
state magnetic configurations, the stray fields are systematically tuned.
Dissipation ... | 1302.0680v1 |
2013-02-09 | Lower bounds on the minimum distance of long codes in the Lee metric | The Gilbert type bound for codes in the title is reviewed, both for small and
large alphabets. Constructive lower bounds better than these existential bounds
are derived from geometric codes, either over Fp or Fp2 ; or over even degree
extensions of Fp: In the latter case the approach is concatena- tion with a
good cod... | 1302.2246v1 |
2013-03-04 | Mansuripur's Paradox | A recent article claims that the Lorentz force law is incompatible with
special relativity. We discuss the "paradox" on which this claim is based. The
resolution depends on whether one assumes a "Gilbert" model for the magnetic
dipole (separated monopoles) or the standard "Ampere" model (current loop). The
former was p... | 1303.0732v2 |
2013-04-09 | Instability of Walker Propagating Domain Wall in Magnetic Nanowires | Stability of the well-known Walker propagating domain wall (DW) solution of
the Landau-Lifshitz-Gilbert equation is analytically investigated.
Surprisingly, the Walker's rigid body propagating DW mode is not stable against
the spin wave/wavepacket emission. In the low field region only stern spin
waves are emitted whil... | 1304.2439v1 |
2013-04-26 | Maximizing Spin Torque Diode Voltage by Optimizing Magnetization Alignment | The optimum condition of the magnetization alignment to maximize the spin
torque diode voltage is derived by solving the Landau-Lifshitz-Gilbert
equation. We show that the optimized diode voltage can be one order of
magnitude larger than that of the conventional alignment where the easy axes of
the free and the pinned ... | 1304.7079v1 |
2013-05-23 | Residual properties of automorphism groups of (relatively) hyperbolic groups | We show that Out(G) is residually finite if G is a one-ended group that is
hyperbolic relative to virtually polycyclic subgroups. More generally, if G is
one-ended and hyperbolic relative to proper residually finite subgroups, the
group of outer automorphisms preserving the peripheral structure is residually
finite. We... | 1305.5403v3 |
2013-05-25 | Thermally-Assisted Spin-Transfer Torque Dynamics in Energy Space | We consider the general Landau-Lifshitz-Gilbert theory underlying the
magnetization dynamics of a macrospin magnet subject to spin-torque effects and
thermal fluctuations. Thermally activated dynamical properties are analyzed by
averaging the full magnetization equations over constant- energy orbits. After
averaging, a... | 1305.5945v2 |
2013-06-10 | Imperfect Construction of Microclusters | Microclusters are the basic building blocks used to construct cluster states
capable of supporting fault-tolerant quantum computation. In this paper, we
explore the consequences of errors on microcluster construction using two error
models. To quantify the effect of the errors we calculate the fidelity of the
construct... | 1306.2202v1 |
2013-06-19 | Weyl Phases in Point-Group Symmetric Superconductors | We study superconductivity in a Weyl semimetal with broken time-reversal
symmetry and stabilized by a point-group symmetry. The resulting
superconducting phase is characterized by topologically protected bulk nodes
and surface states with Fermi arcs. The topological invariant governing the
system is calculated using ch... | 1306.4696v1 |
2013-06-21 | The Polarization Signature of Local Bulk Flows | A large peculiar velocity of the intergalactic medium produces a Doppler
shift of the cosmic microwave background with a frequency-dependent quadrupole
term. This quadrupole will act as a source for polarization of the cosmic
microwave background, creating a large-scale polarization anisotropy if the
bulk flow is local... | 1306.5248v3 |
2013-07-21 | Rigidity in the Positive Mass Theorem with Charge | In this paper we show how a natural coupling of the Dirac equation with the
generalized Jang equation, leads to a proof of the rigidity statement in the
positive mass theorem with charge, without the maximal slicing condition,
provided a solution to the coupled system exists. | 1307.5499v4 |
2014-01-08 | Tri-Dirac Surface Modes in Topological Superconductors | We propose a new type of topological surface modes having cubic dispersion in
three-dimensional topological superconductors. Lower order dispersions are
prohibited by the threefold rotational symmetry and time-reversal symmetry.
Cooper pairing in the bulk changes sign under improper rotations, akin
to$^{3}$He-B. The su... | 1401.1823v1 |
2014-01-09 | Automated Code Generation for Lattice Quantum Chromodynamics and beyond | We present here our ongoing work on a Domain Specific Language which aims to
simplify Monte-Carlo simulations and measurements in the domain of Lattice
Quantum Chromodynamics. The tool-chain, called Qiral, is used to produce
high-performance OpenMP C code from LaTeX sources. We discuss conceptual issues
and details of ... | 1401.2039v1 |
2014-01-13 | Effect of Dzyaloshinskii Moriya interaction on magnetic vortex | The effect of the Dzyaloshinskii Moriya interaction on the vortex in magnetic
microdisk was investigated by micro magnetic simulation based on the Landau
Lifshitz Gilbert equation. Our results show that the DM interaction modifies
the size of the vortex core, and also induces an out of plane magnetization
component at ... | 1401.3292v1 |
2014-01-31 | Self-Oscillation in Spin Torque Oscillator Stabilized by Field-like Torque | The self-oscillation of the magnetization in a spin torque oscillator (STO)
with a perpendicularly magnetized free layer and an in-plane magnetized pinned
layer in the absence of an applied magnetic field was studied by numerically
solving the Landau-Lifshitz-Gilbert equation. It was pointed out that
field-like torque ... | 1401.8088v2 |
2014-02-05 | Spin-polarized transport in ferromagnetic multilayers: An unconditionally convergent FEM integrator | We propose and analyze a decoupled time-marching scheme for the coupling of
the Landau-Lifshitz-Gilbert equation with a quasilinear diffusion equation for
the spin accumulation. This model describes the interplay of magnetization and
electron spin accumulation in magnetic and non-magnetic multilayer structures.
Despite... | 1402.0983v2 |
2014-02-12 | An efficient algorithm for the entropy rate of a hidden Markov model with unambiguous symbols | We demonstrate an efficient formula to compute the entropy rate $H(\mu)$ of a
hidden Markov process with $q$ output symbols where at least one symbol is
unambiguously received. Using an approximation to $H(\mu)$ to the first $N$
terms we give a $O(Nq^3$) algorithm to compute the entropy rate of the hidden
Markov model.... | 1402.2733v2 |
2014-03-24 | Skyrmionic spin Seebeck effect via dissipative thermomagnonic torques | We derive thermomagnonic torque and its "$\beta$-type" dissipative correction
from the stochastic Landau-Lifshitz-Gilbert equation. The "$\beta$-type"
dissipative correction describes viscous coupling between magnetic dynamics and
magnonic current and it stems from spin mistracking of the magnetic order. We
show that t... | 1403.6160v2 |
2014-04-18 | Sparse Approximation, List Decoding, and Uncertainty Principles | We consider list versions of sparse approximation problems, where unlike the
existing results in sparse approximation that consider situations with unique
solutions, we are interested in multiple solutions. We introduce these problems
and present the first combinatorial results on the output list size. These
generalize... | 1404.5190v2 |
2014-04-25 | Linewidth of Power Spectrum Originated from Thermal Noise in Spin Torque Oscillator | A theoretical formula of the linewidth caused by the thermal activation in a
spin torque oscillator with a perpendicularly magnetized free layer and an
in-plane magnetized pinned layer was developed by solving the stochastic
Landau-Lifshitz-Gilbert equation in the energy-phase representation. It is
shown that the linew... | 1404.6558v1 |
2014-08-11 | An optimal irrigation network with infinitely many branching points | The Gilbert-Steiner problem is a mass transportation problem, where the cost
of the transportation depends on the network used to move the mass and it is
proportional to a certain power of the "flow". In this paper, we introduce a
new formulation of the problem, which turns it into the minimization of a
convex function... | 1408.2406v1 |
2014-09-04 | Integer Generalized Splines on Cycles | Let G be a graph whose edges are labeled by positive integers. Label each
vertex with an integer and suppose if two vertices are joined by an edge, the
vertex labels are congruent to each other modulo the edge label. The set of
vertex labels satisfying this condition is called a generalized spline.
Gilbert, Polster, an... | 1409.1481v1 |
2014-09-10 | Proof of the Riemannian Penrose Inequality with Charge for Multiple Black Holes | We present a proof of the Riemannian Penrose inequality with charge in the
context of asymptotically flat initial data sets for the Einstein-Maxwell
equations, having possibly multiple black holes with no charged matter outside
the horizon, and satisfying the relevant dominant energy condition. The proof
is based on a ... | 1409.3271v2 |
2014-09-15 | Enhanced synchronization in an array of spin torque nano oscillators in the presence of oscillating external magnetic field | We demonstrate that the synchronization of an array of electrically coupled
spin torque nano-oscillators (STNO) modelled by
Landau-Lifshitz-Gilbert-Slonczewski (LLGS) equation can be enhanced appreciably
in the presence of a common external microwave magnetic field. The applied
microwave magnetic field stabilizes and e... | 1409.4384v2 |
2014-10-19 | Extensions of the Charged Riemannian Penrose Inequality | In this paper we investigate the extension of the charged Riemannian Penrose
inequality to the case where charges are present outside the horizon. We prove
a positive result when the charge densities are compactly supported, and
present a counterexample when the charges extend to infinity. We also discuss
additional ex... | 1410.5027v2 |
2014-10-23 | Quantum spin dynamics | The classical Landau-Lifshitz equation has been derived from quantum
mechanics. Starting point is the assumption of a non-Hermitian Hamilton
operator to take the energy dissipation into account. The corresponding quantum
mechanical time dependent Schr\"odinger, Liouville and Heisenberg equation have
been described and ... | 1410.6383v1 |
2014-12-04 | Role of Magnetic Field in Self-Oscillation of Nanomagnet Excited by Spin Torque | The critical current of the self-oscillation of spin torque oscillator (STO)
consisting of a perpendicularly magnetized free layer and an in-plane
magnetized pinned layer was studied by solving the Landau-Lifshitz-Gilbert
(LLG) equation. We found that the critical current diverged at certain field
directions, indicatin... | 1412.1532v1 |
2015-01-30 | Memory functions of magnetic skyrmions | Magnetic skyrmion, a swirling spin texture, in chiral magnets is
characterized by (i) nano-scale size ($\sim$1nm -- 100nm), (ii) topological
stability, and (iii) gyro-dynamics. These features are shown to be advantageous
for (a) high-density data-storage, (b) nonvolatile memory, and (c) ultra-low
current and energy cos... | 1501.07650v1 |
2015-02-14 | Energy dissipation in single-domain ferromagnetic nanoparticles: Dynamical approach | We study, both analytically and numerically, the phenomenon of energy
dissipation in single-domain ferromagnetic nanoparticles driven by an
alternating magnetic field. Our interest is focused on the power loss resulting
from the Landau-Lifshitz-Gilbert equation, which describes the precessional
motion of the nanopartic... | 1502.04222v1 |
2015-02-23 | The Positive Mass Theorem for Multiple Rotating Charged Black Holes | In this paper a lower bound for the ADM mass is given in terms of the angular
momenta and charges of black holes present in axisymmetric initial data sets
for the Einstein-Maxwell equations. This generalizes the mass-angular
momentum-charge inequality obtained by Chrusciel and Costa to the case of
multiple black holes.... | 1502.06290v2 |
2015-02-24 | An Upper Bound on the Minimum Distance of LDPC Codes over GF(q) | In [1] a syndrome counting based upper bound on the minimum distance of
regular binary LDPC codes is given. In this paper we extend the bound to the
case of irregular and generalized LDPC codes over GF(q). The comparison to the
lower bound for LDPC codes over GF(q) and to the upper bound for non-binary
codes is done. T... | 1502.06874v1 |
Subsets and Splits
No community queries yet
The top public SQL queries from the community will appear here once available.