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1.
K. V. Samokhin 《JETP Letters》1996,64(11):853-858
We study the statistical mechanics of D-dimensional elastic manifolds, interacting via randomly distributed forces. It is shown, that this model can be mapped onto
the statistical mechanics of disorder-induced roughening of a D-dimensional interface with D transverse degrees of freedom in a disordered medium. The roughness exponent ζ for the lateral deformations is calculated for different kinds of elastic response of the manifolds.
Pis’ma Zh. éksp. Teor. Fiz. 64, No. 11, 801–806 (10 December 1996)
Published in English in the original Russian journal. Edited by Steve Torstveit. 相似文献
2.
The position and momentum space information entropies of weakly interacting trapped atomic Bose–Einstein condensates and spin-polarized
trapped atomic Fermi gases at absolute zero temperature are evaluated. We find that sum of the position and momentum space
information entropies of these quantum systems containing N atoms confined in a D( ≤ 3)-dimensional harmonic trap has a universal form as St(D) = N(a D - b lnN) S_\mathrm{t}^{(D)} = N(a D - b \ln N) , where a ≃ 2.332 and b = 2 for interacting bosonic systems and a ≃ 1.982 and b = 1 for ideal fermionic systems. These results obey the entropic uncertainty relation given by Beckner, Bialynicki-Birula
and Myceilski. 相似文献
3.
We study the limiting behavior of a singularly perturbed Schr?dinger-Poisson system describing a 3-dimensional electron gas
strongly confined in the vicinity of a plane (x, y) and subject to a strong uniform magnetic field in the plane of the gas. The coupled effects of the confinement and of the
magnetic field induce fast oscillations in time that need to be averaged out. We obtain at the limit a system of 2-dimensional
Schr?dinger equations in the plane (x, y), coupled through an effective selfconsistent electrical potential. In the direction perpendicular to the magnetic field,
the electron mass is modified by the field, as the result of an averaging of the cyclotron motion. The main tools of the analysis
are the adaptation of the second order long-time averaging theory of ODEs to our PDEs context, and the use of a Sobolev scale
adapted to the confinement operator. 相似文献
4.
We study a Fermi gas with general translation-invariant many-body interactions on a (v3)-dimensional lattice. A complete analysis is given of the perturbative terms up to second order and the program put forward by N. M. Hugenholtz for the derivative of the Boltzmann equation is verified to second order. 相似文献
5.
在Thomas-Fermi近似条件下,研究了n维广义幂律势阱中Fermi原子气体的最大囚禁范围,给出了n维势阱中气体的实际囚禁体积,导出了状态方程.结果表明,最大囚禁范围和囚禁气体压强不仅与势阱性质有关,也与自由理想Fermi系统的化学势有关.对三维球对称简谐势阱进行了应用,表明在Thomas-Fermi近似有效的前提下,当系统满足条件((kT)/(hω))2 ((16π2g)/
关键词:
Fermi气体
n维势阱')" href="#">n维势阱
最大囚禁范围
状态方程 相似文献
6.
7.
A. López-Ortega 《General Relativity and Gravitation》2006,38(12):1747-1770
Using the monodromy method we calculate the asymptotic quasinormal frequencies of an electromagnetic field moving in D-dimensional Schwarzschild and Schwarzschild de Sitter black holes (D ≥ 4). For the D-dimensional Schwarzschild anti-de Sitter black hole we also compute these frequencies with a similar method. Moreover, we calculate the electromagnetic normal modes of the D-dimensional anti-de Sitter spacetime. 相似文献
8.
Summary We study the effective electron mass at the Fermi level in Kane-type semiconductors on the basis of fourth order in effective
mass theory and taking into account the interactions of the conduction electrons, heavy holes, light holes and split-off holes,
respectively. The results obtained are then compared to those derived on the basis of the well-known three-band Kane model.
It is found, takingn-Hg1−x
Cd
x
Te as an example, that the effective electron mass at the Fermi level in accordance with fourth-order model depends on the
Fermi energy, magnetic quantum number and the electron spin respectively due to the influence of band nonparabolicity only.
The dependence of effective mass on electron spin is due to spin-orbit splitting parameter of the valence band in three-band
Kane model and the Fermi energy due to band nonparabolicity in two-band Kane model. The same mass exhibits an oscillatory
magnetic-field dependence for all the band models as expected since the origin of oscillations in the effective mass in nonparabolic
compounds is the same as that of the Shubnikov-de Hass oscillations. In addition, the corresponding results for parabolic
energy bands have been obtained from the generalized expressions under certain limiting conditions. 相似文献
9.
A. López-Ortega 《General Relativity and Gravitation》2008,40(7):1379-1401
By using the sixth order WKB approximation we calculate for an electromagnetic field propagating in D-dimensional Schwarzschild and Schwarzschild de Sitter (SdS) black holes its quasinormal (QN) frequencies for the fundamental
mode and first overtones. We study the dependence of these QN frequencies on the value of the cosmological constant and the
spacetime dimension. We also compare with the results for the gravitational perturbations propagating in the same background.
Moreover we compute exactly the QN frequencies of the electromagnetic field propagating in D-dimensional massless topological black hole and for the charged D-dimensional Nariai spacetime we calculate exactly the QN frequencies of the coupled electromagnetic and gravitational perturbations. 相似文献
10.
S. K. Srivastava 《International Journal of Theoretical Physics》1992,31(12):2103-2113
Einstein's equations for the generalized (4+D)-dimensional Robertson-Walker model are solved taking the conformally invariant action for the matter field. Compactification of this model is discussed and the compactification time/compactification mass scale for different values ofD is calculated. The resulting 4-dimensional action for gravity is obtained. It is found that a time-dependent cosmological constant is induced which is very large when the cosmic time is small and very small when the cosmic time is large. 相似文献
11.
We construct a physical model to study the effects of dimensional reduction that might have taken place during the inflationary
phase of the universe. The model we propose is a (1 + D)-dimensional (D > 3), nonsingular, spatially homogeneous and isotropic Friedmann model. We consider dimensional reduction to take place in
a stepwise manner and interpret each step as a phase transition. Independent of the details of the process of dimensional
reduction, we impose suitable boundary conditions across the transitions and trace the effects of dimensional reduction to
the currently observable parameters of the universe. In order to exhibit the cosmological features of the proposed model,
we construct a (1 + 4)-dimensional toy model for both closed and open cases of Friedmann geometries. It is shown that in these
models the universe makes transition into the lower dimension when the critical length parameter l
4,3, which signals dimensional reduction, reaches the Planck length in D = 3. The numerical models we present in this paper have the capability of making definite predictions about the cosmological
parameters of the universe such as the Hubble parameter, age and density. 相似文献
12.
We study a hierarchical model of domain walls in aD-dimensional bond disordered Ising model at low temperatures. Using a renormalization group method inspired by the work of Bricmont and Kupiainen for the random field Ising model, we prove the existence of rigid interfaces at low enough temperatures in dimensionsD>3. 相似文献
13.
H. Hinkelmann 《Zeitschrift für Physik B Condensed Matter》1976,25(2):147-153
A simple approximate expression for the electron lifetime() in metals is rederived and discussed for different dimensions. In the 3D-case we get the well known Drude behaviour, i.e. a constant. In one dimension() is strongly frequency-dependent in the IR. The 2D-case is intermediate to the preceding ones. These results are essentially due to the different form of the Fermi surface for an electron gas in one, two and three dimensions. 相似文献
14.
H. Hinkelmann 《Zeitschrift für Physik B Condensed Matter》1976,111(1):147-153
A simple approximate expression for the electron lifetime() in metals is rederived and discussed for different dimensions. In the 3D-case we get the well known Drude behaviour, i.e. a constant. In one dimension() is strongly frequency-dependent in the IR. The 2D-case is intermediate to the preceding ones. These results are essentially due to the different form of the Fermi surface for an electron gas in one, two and three dimensions. 相似文献
15.
We distinguish two different types of irreversible aggregation-accretion of individual particles and successive aggregation of clusters of comparable size. In aggregation of particles which follow trajectories of fractal dimensionD
1, we show that physical limits on the aggregation rate impose a lower bound on the fractal dimensionD
0 of the aggregate. Ind-dimensional space,D
0{d–D}1 + 1. Thus aggregation of ballistic particles, withD
1 = 1, is not fractal. By contrast, cluster aggregates appear to attain a finite, limitingD
0 in high dimensions. We present a soluble model with this property, and argue that it should agree with Sutherland's binary aggregation model in high dimensions. For this model,D
0 depends continuously on a parameter; the exponent is not universal. 相似文献
16.
Einstein equations are derived for D-dimensional space-time that spontaneously compactify to the product M4 × Πi = 1α Mdi in which the metric is taken to be of the generalized Robertson-Walker form. Cosmological solutions for these equations are studied with power law, oscillatory and exponential behaviour for the D-dimensional Einstein-Maxwell, N = 2, D = 10 and N = 1, D = 11 supergravity models. In the Einstein-Maxwell case the presence of a cosmological constant forces the extra dimensions to be static. Nevertheless, it is possible to find solutions with vanishing effective 4 dimensional cosmological constant with an expanding 4-dimensional space-time. In the supergravity models the requirement of having compact extra dimensions restricts the solutions to have expansion only in the 4-dimensional space-time. Matter contribution is added to the energy-momentum tensor in an attempt to find new solutions. 相似文献
17.
A. López-Ortega 《General Relativity and Gravitation》2006,38(11):1565-1591
We calculate the exact values of the quasinormal frequencies for an electromagnetic field and a gravitational perturbation
moving in D-dimensional de Sitter spacetime (D ≥ 4). We also study the quasinormal modes of a real massive scalar field and compare our results with those of other references. 相似文献
18.
Due to the scale invariance,the thermodynamic laws of strongly interacting limit unitary Fermi gas can be similar to those of non-interacting ideal gas.For example,the virial theorem between pressure and energy density of the ideal gas P=2E/3V is still satisfied by the unitary Fermi gas.This paper analyses the sound velocity of unitary Fermi gases with the quasi-linear approximation.For comparison,the sound velocities for the ideal Boltzmann,Bose and Fermi gas are also given.Quite interestingly,the sound velocity formula for the ideal non-interacting gas is found to be satisfied by the unitary Fermi gas in different temperature regions. 相似文献
19.
Tensor network states are used to approximate ground states of local Hamiltonians on a lattice in D spatial dimensions. Different types of tensor network states can be seen to generate different geometries. Matrix product
states (MPS) in D=1 dimensions, as well as projected entangled pair states (PEPS) in D>1 dimensions, reproduce the D-dimensional physical geometry of the lattice model; in contrast, the multi-scale entanglement renormalization ansatz (MERA)
generates a (D+1)-dimensional holographic geometry. Here we focus on homogeneous tensor networks, where all the tensors in the network are
copies of the same tensor, and argue that certain structural properties of the resulting many-body states are preconditioned
by the geometry of the tensor network and are therefore largely independent of the choice of variational parameters. Indeed,
the asymptotic decay of correlations in homogeneous MPS and MERA for D=1 systems is seen to be determined by the structure of geodesics in the physical and holographic geometries, respectively;
whereas the asymptotic scaling of entanglement entropy is seen to always obey a simple boundary law—that is, again in the
relevant geometry. This geometrical interpretation offers a simple and unifying framework to understand the structural properties
of, and helps clarify the relation between, different tensor network states. In addition, it has recently motivated the branching
MERA, a generalization of the MERA capable of reproducing violations of the entropic boundary law in D>1 dimensions. 相似文献
20.
The rearrangement of the Fermi surface in a diluted two-dimensional electron gas beyond the topological quantum critical point has been examined within an approach based on the Landau theory of Fermi liquid and a nonperturbative functional method. The possibility of a transition of the first order in the coupling constant at zero temperature between the states with a three-sheet Fermi surface and a transition of the first order in temperature between these states at a fixed coupling constant has been shown. It has also been shown that a topological crossover, which is associated with the joining of two sheets of the Fermi surface and is characterized by the maxima of the density of states N(T) and ratio C(T)/T of the specific heat to the temperature, occurs at a very low temperature T ⋄ determined by the structure of a state with the three-sheet Fermi surface. A momentum region where the distribution n(p, T) depends slightly on the temperature, which is manifested in the maximum of the specific heat C(T) near T *, appears through a crossover at temperatures T ∼ T * > T ⋄. It has been shown that the flattening of the single-particle spectrum of the strongly correlated two-dimensional electron gas results in the crossover from the Fermi liquid behavior to a non-Fermi liquid one with the density of states N(T) ∝ T −α with the exponent α }~ 2/3. 相似文献