共查询到20条相似文献,搜索用时 343 毫秒
1.
I. A. Fomin 《JETP Letters》2011,93(3):144-146
It is shown that weak correlations between pair-breaking impurities in superconductors influence the temperature dependence
of the order parameter within the Ginzburg-Landau region if correlation radius of impurities R is greater than the coherence length of the superconductor ξ0. The dependence of the square of the average order parameter on a temperature difference T
c
− T changes its slope in a region $
\xi _0 \sqrt {{{T_c } \mathord{\left/
{\vphantom {{T_c } {\left( {T_c - T} \right)}}} \right.
\kern-\nulldelimiterspace} {\left( {T_c - T} \right)}}} \sim R
$
\xi _0 \sqrt {{{T_c } \mathord{\left/
{\vphantom {{T_c } {\left( {T_c - T} \right)}}} \right.
\kern-\nulldelimiterspace} {\left( {T_c - T} \right)}}} \sim R
. The influence of correlations of impurities on other thermodynamic properties of superconductors is discussed. 相似文献
2.
Todd A. Oliynyk 《Communications in Mathematical Physics》2010,295(2):431-463
We prove the existence of a large class of one parameter families of solutions to the Einstein-Euler equations that depend
on the singular parameter e = vT/c{\epsilon=v_T/c}
(0 < e < e0){(0< \epsilon < \epsilon_0)}, where c is the speed of light, and v
T
is a typical speed of the gravitating fluid. These solutions are shown to exist on a common spacetime slab
M @ [0,T)×\mathbb T3{M\cong [0,T)\times \mathbb {T}^3}, and converge as
e\searrow 0{\epsilon \searrow 0} to a solution of the cosmological Poisson-Euler equations of Newtonian gravity. Moreover, we establish that these solutions
can be expanded in the parameter e{\epsilon} to any specified order with expansion coefficients that satisfy e{\epsilon}-independent (nonlocal) symmetric hyperbolic equations. 相似文献
3.
I. S. Burmistrov 《JETP Letters》2004,79(4):177-182
We study the conductivity of two-dimensional interacting electrons on the half-filled Nth Landau level with N?1 in the presence of quenched disorder. The existence of the unidirectional charge-density wave state at temperature T<T c , where T c is the transition temperature, leads to the anisotropic conductivity tensor. We find that the leading anisotropic corrections are proportional to (T c ?T)/T c just below the transition, in accordance with the experimental findings. Above T c , the correlations corresponding to the unidirectional charge-density wave state below T c result in corrections to the conductivity proportional to \(\sqrt {{{T_c } \mathord{\left/ {\vphantom {{T_c } {T - T_c }}} \right. \kern-\nulldelimiterspace} {T - T_c }}} \). 相似文献
4.
《Nuclear Physics B》1996,469(3):419-444
The pressure and the energy density of the SU(3) gauge theory are calculated on lattices with temporal extent Nτ = 4, 6 and 8 and spatial extent Nσ = 16 and 32. The results are then extrapolated to the continuum limit. In the investigated temperature range up to five times Tc we observe a 15% deviation from the ideal gas limit. We also present new results for the critical temperature on lattices with temporal extent Nτ = 8 and 12. At the corresponding critical couplings the string tension is calculated on 324 lattices to fix the temperature scale. An extrapolation to the continuum limit yields Tc/√σ = 0.629(3). We furthermore present results on the electric and magnetic condensates as well as the temperature dependence of the spatial string tension. These observables suggest that the temperature dependent running coupling remains large even at T ≅ 5Tc. For the spatial string tension we find √σs/T=0.566(13)g22(T) with g2 (5Tc) ≅ 1.5. 相似文献
5.
Lorenzo Iorio 《General Relativity and Gravitation》2010,42(1):199-208
Analytical and numerical calculations show that a putative temporal variation of the speed of light c, with the meaning of space-time structure constant c
ST, assumed to be linear over timescales of about one century, would induce a secular precession of the longitude of the pericenter
v{\varpi} of a test particle orbiting a spherically symmetric body. By comparing such a predicted effect to the corrections D[(v)\dot]{\Delta\dot\varpi} to the usual Newtonian/Einsteinian perihelion precessions of the inner planets of the Solar System, recently estimated by
E.V. Pitjeva by fitting about one century of modern astronomical observations with the standard classical/relativistic dynamical
force models of the EPM epehemerides, we obtained [(c)\dot]/c = (0.5±2)×10-7 yr-1{\dot c/c =(0.5\pm 2)\times 10^{-7} {\rm yr}^{-1}} . Moreover, the possibility that [(c)\dot]/c 1 0{\dot c/c\neq 0} over the last century is ruled out at 3−12σ level by taking the ratios of the perihelia for different pairs of planets. Our results are independent of any measurement
of the variations of other fundamental constants which may be explained by a variation of c itself (with the meaning of electromagnetic constant c
EM). It will be important to repeat such tests if and when other teams of astronomers will estimate their own corrections to
the standard Newtonian/Einsteinian planetary perihelion precessions with different ephemerides. 相似文献
6.
T. Lappi 《The European Physical Journal C - Particles and Fields》2011,71(8):1699
A natural framework to understand the energy dependence of bulk observables from lower energy experiments to the LHC is provided
by the Color Glass Condensate, which leads to a “geometrical scaling” in terms of an energy-dependent saturation scale Q
s. The measured charged multiplicity, however, seems to grow faster ( ~ ?s0.3{\sim}\sqrt{s}^{0.3}) in nucleus–nucleus collisions than it does for protons ( ~ ?s0.2{\sim} \sqrt{s}^{0.2}), violating the expectation from geometric scaling. We argue that this difference between pp and AA collisions can be understood
from the effect of DGLAP evolution on the value of the saturation scale, and is consistent with gluon saturation observations
at HERA. 相似文献
7.
It is shown that the slope of the upper critical field
in superconductors with d pairing drops rapidly with increasing concentration of normal impurities, while in superconductors with anisotropic s pairing
increases and reaches the well-known asymptotic level characteristic for the isotropic case. This difference makes it possible,
in principle, to employ measurements of H
c
2 in disordered superconductors as an experimental method for determining the type of pairing in high-T
c
superconductors and systems with heavy fermions.
Pis’ma Zh. éksp. Teor. Fiz. 63, No. 5, 347–352 (10 March 1996) 相似文献
8.
Zhi Yang Xing-Gang Wu Li-Cheng Deng Jia-Wei Zhang Gu Chen 《The European Physical Journal C - Particles and Fields》2011,71(3):1563
In Deng et al. (Eur. Phys. J. C 70:113, 2010), we have dealt with the production of the two color-singlet S-wave (c[`(b)])(c\bar{b})-quarkonium states Bc(|(c[`(b)])1[1S0]?)B_{c}(|(c\bar {b})_{\mathbf{1}}[^{1}S_{0}]\rangle) and B*c(|(c[`(b)])1[3S1]?)B^{*}_{c}(|(c\bar{b})_{\mathbf{1}}[^{3}S_{1}]\rangle) through the Z
0 boson decays. As an important sequential work, we make a further discussion on the production of the more complicated P-wave excited (c[`(b)])(c\bar{b})-quarkonium states, i.e. |(c[`(b)])1[1P1]?|(c\bar{b})_{\mathbf{1}}[^{1}P_{1}]\rangle and |(c[`(b)])1[3PJ]?|(c\bar{b})_{\mathbf{1}}[^{3}P_{J}]\rangle (with J=(1,2,3)). More over, we also calculate the channel with the two color-octet quarkonium states |(c[`(b)])8[1S0]g?|(c\bar{b})_{\mathbf{8}}[^{1}S_{0}]g\rangle and |(c[`(b)])8[3S1]g?|(c\bar{b})_{\mathbf{8}}[^{3}S_{1}]g\rangle, whose contributions to the decay width maybe at the same order of magnitude as that of the color-singlet P-wave states according to the naive nonrelativistic quantum chromodynamics scaling rules. The P-wave states shall provide sizable contributions to the B
c
production, whose decay width is about 20% of the total decay width
\varGamma Z0? Bc\varGamma _{Z^{0}\to B_{c}}. After summing up all the mentioned (c[`(b)])(c\bar {b})-quarkonium states’ contributions, we obtain
\varGamma Z0? Bc=235.9+352.8-122.0\varGamma _{Z^{0}\to B_{c}}=235.9^{+352.8}_{-122.0} KeV, where the errors are caused by the main sources of uncertainty. 相似文献
9.
10.
Jun Yin 《Journal of statistical physics》2010,141(4):683-726
We derive an upper bound on the free energy of a Bose gas at density ϱ and temperature T. In combination with the lower bound derived previously by Seiringer (Commun. Math. Phys. 279(3): 595–636, 2008), our result proves that in the low density limit, i.e., when a
3
ϱ≪1, where a denotes the scattering length of the pair-interaction potential, the leading term of Δf, the free energy difference per volume between interacting and ideal Bose gases, is equal to 4pa(2r2-[r-rc]2+)4\pi a(2\varrho^{2}-[\varrho-\varrho_{c}]^{2}_{+}). Here, ϱ
c
(T) denotes the critical density for Bose–Einstein condensation (for the ideal Bose gas), and [⋅]+=max {⋅,0} denotes the positive part. 相似文献
11.
Christian Schmidt RBC-Bielefeld Collaboration HotQCD Collaboration 《Nuclear Physics A》2009,820(1-4):41c
We present results on the QCD equation of state, obtained with two different improved dynamical staggered fermion actions and almost physical quark masses. Lattice cut-off effects are discussed in detail as results for three different lattice spacings are available now, i.e. results have been obtained on lattices with temporal extent of Nτ = 4, 6 and 8. Furthermore we discuss the Taylor expansion approach to non-zero baryon chemical potential by means of an expansion of the pressure. We use the expansion coefficients to calculate various fluctuations and correlations among hadronic charges. We find that the correlations reproduce the qualitative behavior of the resonance gas model below Tc and start to agree with the free gas predictions for T1.5Tc. 相似文献
12.
T. B. Charikova G. I. Kharus N. G. Shelushinina O. E. Petukhova A. A. Ivanov 《Journal of Experimental and Theoretical Physics》2012,114(3):496-502
We report on the results of analyzing the temperature dependences of the resistivity of the Nd2 − x
Ce
x
CuO4 + δ electronic superconductor with x = 0.14 (underdoped range), x = 0.15 (optimal doping), and x = 0.18 (overdoped range) and with various degrees of annealing in an oxygen-free atmosphere in magnetic fields up to H = 90 kOe (H ‖ c, J ‖ ab) in the temperature range T = (0.4–300) K. It is shown that the observed differences in the dependences of the slope of the upper critical field (dHc2 /dT)|Tc (dH_{c2} /dT)|_{T_c } on the degree of disorder in the Nd2 − x
Ce
x
CuO4 + δ system upon a change in the cerium doping level indicate a change in the symmetry of d-type pairing to anisotropic s pairing. 相似文献
13.
Su Houng Lee Shigehiro Yasui 《The European Physical Journal C - Particles and Fields》2009,64(2):283-295
Based on the color–spin interaction in diquarks, we argue why some multiquark configurations could be stable against strong
decay when heavy quarks are included. After showing the stability of previously discussed states we identify new possible
stable states. These are the T0cb(ud[`(c)][`(b)])T^{0}_{cb}(ud\bar{c}\bar{b}) tetraquark, the
\varTheta bs(udus[`(b)])\varTheta _{bs}(udus\bar{b}) pentaquark and the H
c
(udusuc) dibaryon, and so forth. 相似文献
14.
Kh. K. Olimov S. L. Lutpullaev B. S. Yuldashev Y. H. Huseynaliyev A. K. Olimov 《The European Physical Journal A - Hadrons and Nuclei》2010,44(1):43-54
The production of D++ \Delta^{{++}}_{} and D0 \Delta^{0}_{} resonances on oxygen nuclei in 16O + p interactions at 3.25A GeV/c was investigated with 4p \pi acceptance. The masses and widths of the resonances were obtained from an analysis of the experimental and background invariant-mass
distributions of pp± \pi^{{\pm}}_{} pairs. The fractions of charged pions coming from D++ \Delta^{{++}}_{} and D0 \Delta^{0}_{} decay were estimated. The momentum, kinetic energy, and emission angle distributions of D++ \Delta^{{++}}_{} and D0 \Delta^{0}_{} resonances were reconstructed in the oxygen nucleus rest frame. The slope parameters, T0 , of the reconstructed spectra of invariant cross-sections of D++ \Delta^{{++}}_{} and D0 \Delta^{0}_{} resonances, produced on oxygen nuclei in 16O + p interactions at 3.25A GeV/c , were determined. 相似文献
15.
Nadav Drukker Marcos Mariño Pavel Putrov 《Communications in Mathematical Physics》2011,306(2):511-563
The partition function of N=6{\mathcal{N}=6} supersymmetric Chern–Simons-matter theory (known as ABJM theory) on
\mathbbS3{\mathbb{S}^3} , as well as certain Wilson loop observables, are captured by a zero dimensional super-matrix model. This super–matrix model
is closely related to a matrix model describing topological Chern–Simons theory on a lens space. We explore further these
recent observations and extract more exact results in ABJM theory from the matrix model. In particular we calculate the planar
free energy, which matches at strong coupling the classical IIA supergravity action on
AdS4×\mathbbC\mathbbP3{{\rm AdS}_4\times\mathbb{C}\mathbb{P}^3} and gives the correct N
3/2 scaling for the number of degrees of freedom of the M2 brane theory. Furthermore we find contributions coming from world-sheet
instanton corrections in
\mathbbC\mathbbP3{\mathbb{C}\mathbb{P}^3} . We also calculate non-planar corrections, both to the free energy and to the Wilson loop expectation values. This matrix
model appears also in the study of topological strings on a toric Calabi–Yau manifold, and an intriguing connection arises
between the space of couplings of the planar ABJM theory and the moduli space of this Calabi–Yau. In particular it suggests
that, in addition to the usual perturbative and strong coupling (AdS) expansions, a third natural expansion locus is the line
where one of the two ’t Hooft couplings vanishes and the other is finite. This is the conifold locus of the Calabi–Yau, and
leads to an expansion around topological Chern–Simons theory. We present some explicit results for the partition function
and Wilson loop observables around this locus. 相似文献
16.
We study effects of static inter-qubit interactions on the stability of the Grover quantum search algorithm. Our numerical and analytical results show existence of regular and chaotic phases depending on the imperfection strength
e\varepsilon
. The critical border
ec\varepsilon_c
between two phases drops polynomially with the number of qubits n
q
as
ec ~ nq-3/2\varepsilon_c \sim n_q^{-3/2}
. In the regular phase
(e < ec)(\varepsilon < \varepsilon_c)
the algorithm remains robust against imperfections showing the efficiency gain
ec / e\varepsilon_c / \varepsilon
for
e >~2-nq/2\varepsilon \gtrsim 2^{-n_q/2}
. In the chaotic phase
$(\varepsilon > \varepsilon_c)$(\varepsilon > \varepsilon_c)
the algorithm is completely destroyed. 相似文献
17.
We study the two-dimensional Gross-Pitaevskii theory of a rotating Bose gas in a disc-shaped trap with Dirichlet boundary
conditions, generalizing and extending previous results that were obtained under Neumann boundary conditions. The focus is
on the energy asymptotics, vorticity and qualitative properties of the minimizers in the parameter range |log ε|≪Ω≲ε
−2|log ε|−1 where Ω is the rotational velocity and the coupling parameter is written as ε
−2 with ε≪1. Three critical speeds can be identified. At
\varOmega = \varOmegac1 ~ |loge|\varOmega=\varOmega_{\mathrm{c_{1}}}\sim |\log\varepsilon| vortices start to appear and for
|loge| << \varOmega < \varOmegac2 ~ e-1|\log\varepsilon|\ll\varOmega< \varOmega_{\mathrm{c_{2}}}\sim \varepsilon^{-1} the vorticity is uniformly distributed over the disc. For
\varOmega 3 \varOmega c2\varOmega\geq\varOmega _{\mathrm{c_{2}}} the centrifugal forces create a hole around the center with strongly depleted density. For Ω≪ε
−2|log ε|−1 vorticity is still uniformly distributed in an annulus containing the bulk of the density, but at
\varOmega = \varOmegac3 ~ e-2|loge|-1\varOmega=\varOmega_{\mathrm {c_{3}}}\sim\varepsilon ^{-2}|\log\varepsilon |^{-1} there is a transition to a giant vortex state where the vorticity disappears from the bulk. The energy is then well approximated
by a trial function that is an eigenfunction of angular momentum but one of our results is that the true minimizers break
rotational symmetry in the whole parameter range, including the giant vortex phase. 相似文献
18.
In this paper, we consider the global wellposedness of the 3-D incompressible anisotropic Navier-Stokes equations with initial
data in the critical Besov-Sobolev type spaces B{\mathcal{B}} and
B-\frac12,\frac124{\mathcal{B}^{-\frac12,\frac12}_4} (see Definitions 1.1 and 1.2 below). In particular, we proved that there exists a positive constant C such that (ANS
ν
) has a unique global solution with initial data u0 = (u0h, u03){u_0 = (u_0^h, u_0^3)} which satisfies
||u0h||B exp(\fracCn4 ||u03||B4) £ c0n{\|u_0^h\|_{\mathcal{B}} \exp\bigl(\frac{C}{\nu^4} \|u_0^3\|_{\mathcal{B}}^4\bigr) \leq c_0\nu} or
||u0h||B-\frac12,\frac124 exp(\fracCn4 ||u03||B-\frac12,\frac1244) £ c0n{\|u_0^h\|_{\mathcal{B}^{-\frac12,\frac12}_{4}} \exp \bigl(\frac{C}{\nu^4} \|u_0^3\|_{\mathcal{B}^{-\frac12,\frac12}_{4}}^4\bigr)\leq c_0\nu} for some c
0 sufficiently small. To overcome the difficulty that Gronwall’s inequality can not be applied in the framework of Chemin-Lerner
type spaces, [(Lpt)\tilde](B){\widetilde{L^p_t}(\mathcal{B})}, we introduced here sort of weighted Chemin-Lerner type spaces, [(L2t, f)\tilde](B){\widetilde{L^2_{t, f}}(\mathcal{B})} for some apropriate L
1 function f(t). 相似文献
19.
G. Seregin 《Communications in Mathematical Physics》2012,312(3):833-845
We show that a necessary condition for T to be a potential blow up time is limt- T ||v(·,t)||L3=¥{\lim\nolimits_{t\uparrow T} \|v(\cdot,t)\|_{L_3}=\infty}. 相似文献
20.
We consider the Glauber dynamics for the 2D Ising model in a box of side L, at inverse temperature β and random boundary conditions τ whose distribution P either stochastically dominates the extremal plus phase (hence the quotation marks in the title) or is stochastically dominated by the extremal minus phase. A particular case is when P is concentrated on the homogeneous configuration identically equal to + (equal to ?). For β large enough we show that for any ${\varepsilon >0 }We consider the Glauber dynamics for the 2D Ising model in a box of side L, at inverse temperature β and random boundary conditions τ whose distribution P either stochastically dominates the extremal plus phase (hence the quotation marks in the title) or is stochastically dominated
by the extremal minus phase. A particular case is when P is concentrated on the homogeneous configuration identically equal to + (equal to −). For β large enough we show that for any ${\varepsilon >0 }${\varepsilon >0 } there exists c=c(b,e){c=c(\beta,\varepsilon)} such that the corresponding mixing time T
mix satisfies limL?¥ P(Tmix 3 exp(cLe)) = 0{{\rm lim}_{L\to\infty}\,{\bf P}\left(T_{\rm mix}\ge {\rm exp}({cL^\varepsilon})\right) =0}. In the non-random case τ ≡ + (or τ ≡ −), this implies that Tmix £ exp(cLe){T_{\rm mix}\le {\rm exp}({cL^\varepsilon})}. The same bound holds when the boundary conditions are all + on three sides and all − on the remaining one. The result,
although still very far from the expected Lifshitz behavior T
mix = O(L
2), considerably improves upon the previous known estimates of the form
Tmix £ exp(c L\frac 12 + e){T_{\rm mix}\le {\rm exp}({c L^{\frac 12 + \varepsilon}})}. The techniques are based on induction over length scales, combined with a judicious use of the so-called “censoring inequality”
of Y. Peres and P. Winkler, which in a sense allows us to guide the dynamics to its equilibrium measure. 相似文献