共查询到20条相似文献,搜索用时 31 毫秒
1.
Horng-Tzer Yau 《Communications in Mathematical Physics》1996,181(2):367-408
Let
denote the grand canonical Gibbs measure of a lattice gas in a cube of sizeL with the chemical potential and a fixed boundary condition. Let
be the corresponding canonical measure defined by conditioning
on
. Consider the lattice gas dynamics for which each particle performs random walk with rates depending on near-by particles. The rates are chosen such that, for everyn andL fixed,
is a reversible measure. Suppose that the Dobrushin-Shlosman mixing conditions holds for
forall chemical potentials . We prove that
for any probability densityf with respect to
; here the constant is independent ofn orL andD denotes the Dirichlet form of the dynamics. The dependence onL is optimal.Research partially supported by U.S. National Science Foundations grant 9403462, Sloan Foundation Fellowship and David and Lucile Packard Foundation Fellowship. 相似文献
2.
Within the general framework ofC*-algebra approach to mathematical foundation of statistical mechanics, we prove a theorem which gives a natural explanation for the appearance of the chemical potential (as a thermodynamical parameter labelling equilibrium states) in the presence of a symmetry (under gauge transformations of the first kind). As a symmetry, we consider a compact abelian groupG acting as *-automorphisms of aC*-algebra
(quasi-local field algebra) and commuting (elementwise) with the time translation automorphisms
t
of
. Under a technical assumption which is satisfied by examples of physical interest, we prove that the set of all extremal
t
-KMS states (pure phases) ofG-fixed-point subalgebra
(quasi-local observable algebra) of
satisfying a certain faithfulness condition is in one-to-one correspondence with the set of all extremalG-invariant
t
·
t
-KMS states – of
with varying over one-parameter subgroups ofG (the specification of being the specification of the chemical potential), where the correspondence is that the restriction of – to
is . 相似文献
3.
Neutrinoless double-beta decay within Minimal Supersymmetric Standard Model with gauge mediated supersymmetry breaking is considered. Limits on R-parity breaking constant
coming from non-observability of 0 in 76Ge are found. The dependence of
on different parameters at the messenger scale M are shown, with special attention paid to nuclear part of calculations. We have found that
strongly depends on the effective supersymmetry breaking scale only and deduced limits imposed on this non-standard parameter by the germanium experiment. 相似文献
4.
Toshiharu Kawai 《General Relativity and Gravitation》1986,18(10):995-1018
We develop a gauge theory of gravity on the basis of the principal fiber bundle over the four-dimensional space-timeM with the covering groupP¯
0
of the proper orthochronous Poincaré group. The field components
are constructed with the connection coefficients
,
and with a Higgs-type field. A Lorentz metricg is introduced with
, which are then identified with the components of duals of the Vierbein fields. Associated with there is a spinor structure onM. For Lagrangian densityL, which is a function of
,
,, matter field , and oftheir first derivatives, we give the conditions imposed by the requirement of the
gauge invariance. The Lagrangian densityL is restricted to be of the formL =L
tot
(, T
klm
,R
klmn
,
k
, ), in whichT
klm
,R
klmn
are the field strengths of
,
, respectively. Identities and conservation laws following from the
gauge invariance are given. Particularly noteworthy is the fact that the energy momentum conservation law follows from theinternal translational invariance. The field equation of is automatically satisfied, if those of
and of are both satisfied. The possible existence of matter fields with intrinsic energy momentum is pointed out. When is a field with vanishing intrinsic energy momentum, the present theory practically agrees with the conventional Poincaré gauge theory of gravity, except for the seemingly trivial terms in the expression of the spin-angular momentum density. A condition leading to a Riemann-Cartan space-time is given. The field holds a key position in the formulation. 相似文献
5.
The theorem that each derivation of aC*-algebra
extends to an inner derivation of the weak-operator closure (
)– of
in each faithful representation of
is proved in sketch and used to study the automorphism group of
in its norm topology. It is proved that the connected component of the identity in this group contains the open ball of radius 2 with centerl and that each automorphism in extends to an inner automorphism of (
)–.Research conducted with the partial support of the NSF and ONR. 相似文献
6.
It is shown that the elliptic algebra
at the critical level c = –2 has a multidimensional center containing some trace-like operators t(z). A family of Poisson structures indexed by a non-negative integer and containing the q-deformed Virasoro algebra is constructed on this center. We show also that t(z) close an exchange algebra when p
m = q
c+2 for
, they commute when in addition p = q
2k
for k integer non-zero, and they belong to the center of
when k is odd. The Poisson structures obtained for t(z) in these classical limits contain the q-deformed Virasoro algebra, characterizing the structures at p q
2k
as new
algebras. 相似文献
7.
R. F. Streater 《Communications in Mathematical Physics》1967,6(4):233-247
We consider a lattice of spin 1/2 ions, described by the discrete form of the current commutation relationsJ
i
J
(i)
=1/2, [J
i
,J
i
]=i
ij
J
i
where =1, 2, 3 andi label the lattice sites. The algebra is realized as the Clifford algebra
over a Hilbert space. The equations of motion are specified by a formal Hamiltonian of the Heisenberg form:
, wheref
ij
0 and only a finite numberQ of ions are linked to any given lattice site. We prove that the Hamiltonian is non-negative in a representation of
, and has a ground state exhibiting ferromagnetism. The time displacement group acts continuously on
, inducing automorphisms.
is asymptotically abelian with respect to the space translations of the lattice.The model is an example of an algebraic quantum field theory and possesses a broken symmetry, the rotation group 0(3). The consequent Goldstone theorem is proved, namely, there is no energy gap in the spectrum ofH. 相似文献
8.
G. Dietz K. Richter F. Stein H. C. Schäfer 《Zeitschrift für Physik B Condensed Matter》1990,81(2):223-228
Dependent on
is produced through electrodeposition in three modifications: microcrystalline if
, amorphous if
and in a mixed state containing both components if
. The interpretation of results of large and small angle X-ray scattering, of measurements of the coercivity and of the mechanical density shows that the three modifications consist of two phases. The structure of the grain boundary phase in the microcrystalline alloys differs considerably from that of the amorphous phase. This arises from the dependence of the atomic volume on the average phosphorus content
. The volume fraction of the crystalline component decreases with increasing
up to
. But even in alloys revealing X-ray patterns without any peaks coming from crystalline particles small angle X-ray scattering indicates the existence of metal-rich inclusions occupying some percent of the total volume. 相似文献
9.
James D. Edmonds Jr. 《Foundations of Physics》1978,8(5-6):439-444
The 2-by-2 Pauli matrix algebra is used to write the 1-by-4 Dirac field in anequivalent 2-by-2 matrix . The current 4-vectors
and *µ are then compared and the latter is shown to not be easily interpretable as a probability density, and also tocontain
. 相似文献
10.
Stan Gudder 《Foundations of Physics》1999,29(6):877-897
This article begins with a review of the framework of fuzzy probability theory. The basic structure is given by the -effect algebra of effects (fuzzy events)
and the set of probability measures
on a measurable space
. An observable
is defined, where
is the value space of X. It is noted that there exists a one-to-one correspondence between states on
and elements of
and between observables
and -morphisms from
to
. Various combinations of observables are discussed. These include compositions, products, direct products, and mixtures. Fuzzy stochastic processes are introduced and an application to quantum dynamics is considered. Quantum effects are characterized from among a more general class of effects. An alternative definition of a statistical map
is given and it is shown that any statistical map has a unique extension to a statistical operator. Finally, various combinations of statistical maps are discussed and their relationships to the corresponding combinations of observables are derived. 相似文献
11.
We have examined the influence of parametric noise on the solution behavioru(t, x) of a nonlinear initial value() problem arising in cell kinetics. In terms of ensemble statistics, the eventual limiting solution mean
and variance
are well-characterized functions of the noise statistics, and
and
depend on . When noise is continuously present along the trajectory,
and
are independent of the noise statistics and . However, in their evolution toward
and
, both
u
(t, x) and
u
2
(t, x) depend on the noise and. 相似文献
12.
Bertfried Fauser 《International Journal of Theoretical Physics》2001,40(1):399-412
Daviau showed the equivalence of matrix Dirac theory, formulated within a spinor bundle
, to a Clifford algebraic formulation within space Clifford algebra
Pauli algebra (matrices) biquaternions. We will show, that Daviau's map :
is an isomorphism. It is shown that Hestenes' and Parra's formulations are equivalent to Daviau's Clifford algebra formulation, which uses outer automorphisms. The connection between different formulations is quite remarkable, since it connects the left and right action on the Pauli algebra itself viewed as a bi-module with the left (resp. right) action of the enveloping algebra
. The isomorphism established in this article and given by Daviau's map does clearly show that right and left actions are of similar type. This should be compared with attempts of Hestenes, Daviau, and others to interprete the right action as the iso-spin freedom. 相似文献
13.
S. L. Woronowicz 《Communications in Mathematical Physics》1973,30(1):55-67
The investigation of purifications of factor states has been carried on. It is shown, that any factor state of aC*-algebra admits at most one purification
, so one can introduce the purification map
. It turns out, that the Powers and Størmer inequality is valid in this general situation. 相似文献
14.
Mark Freidlin 《Journal of statistical physics》2004,117(3-4):617-634
According to the Smoluchowski–Kramers approximation, solution q
t
of the equation
, where
is the White noise, converges to the solution of equation
as µ 0. Many asymptotic problems for the last equation were studied in recent years. We consider relations between asymptotics for the first order equation and the original second order equation. Homogenization, large deviations and stochastic resonance, approximation of Brownian motion W
t
by a smooth stochastic process, stationary distributions are considered. 相似文献
15.
M. Kobel D. Antreasyan H. W. Bartels D. Besset Ch. Bieler J. K. Bienlein A. Bizetti E. D. Bloom I. Brock K. Brockmüller et al. 《Zeitschrift fur Physik C Particles and Fields》1992,53(2):193-205
Using the Crystal Ball detector at thee
+
e
– storage ring DORIS II, we have measured the branching fraction to muon pairsB
of the (1S) and (2S) resonances and for the first time the product of the muonic partial width
and the branching fraction to electronsB
ee
for both resonances. We obtain
相似文献
16.
Horacio G. Rotstein Amy Novick-Cohen Rina Tannenbaum 《Journal of statistical physics》1998,90(1-2):119-143
Metallic cluster growth within a reactive polymer matrix is modeled by augmenting coagulation equations to include the influence of side reactions of metal atoms with the polymer matrix:
where > 0 and where c
k denotes the concentration of the kth cluster and p denotes the concentration of reactive sites available within the polymer matrix for reaction with metallic atoms. The initial conditions are required to be non-negative and satisfy
and p(0) = p
0. We assume that
for 01, which encompasses both bond linking kernels (R
jk
= j
k
) and surface reaction kernels (R
jk
= j
+ k
). Our analytical and numerical results indicate that the side reactions delay gelation in some cases and inhibit gelation in others. We provide numerical evidence that gelation occurs for the classical coagulation equations ( = 0) with the bond linking kernel (d ) for 1/2<1. We examine the relative fraction of metal atoms, which coagulate compared to those which interact with the polymer matrix, and demonstrate in particular a linear dependence on –1 in the limiting case R
= jk
, p
0=1. 相似文献
17.
A. Bartl W. Majerotto B. Mösslacher N. Oshimo 《Zeitschrift fur Physik C Particles and Fields》1991,52(4):677-684
We present a detailed study of
and
and the subsequent decays of
,
, and
at the LHC
. We explore the relevant supersymmetry parameter range. We calculate the cross sections as well as the rates for interesting signatures such as the production of one or two leptons on the lepton side. 相似文献
18.
We present some new identities satisfied by double and triple products of the Weyl tensorW
v and its dual
.Partially supported by C.N.Pq. 相似文献
19.
In ordinary quantum mechanics for finite systems, the time evolution induced by Hamiltonians of the form
is studied from the point of view of *-automorphisms of the CCRC*-algebra
(see Ref. [1, 2]). It is proved that those Hamiltonians do not induce *-automorphisms of this algebra in the cases: a)
and b)V L
(,dx) L
1 (,dx), except when the potential is trivial. 相似文献
20.
We consider the Dirichlet Laplacian for astrip in
with one straight boundary and a width
, where $f$ is a smooth function of acompact support with a length 2b. We show that in the criticalcase,
, the operator has nobound statesfor small
.On the otherhand, a weakly bound state existsprovided
. In thatcase, there are positive c
1,c
2 suchthat the corresponding eigenvalue satisfies
for all
sufficiently small. 相似文献
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