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1.
Mykhaylo Tyomkyn 《Journal of statistical physics》2012,148(6):1072-1075
We analyze the abelian sandpile model on ℤ d for the starting configuration of n particles in the origin and 2d−2 particles otherwise. We give a new short proof of the theorem of Fey, Levine and Peres (J. Stat. Phys. 198:143–159, 2010) that the radius of the toppled cluster of this configuration is O(n 1/d ). 相似文献
2.
Jun Zhang Hua Nan Yuan-Hong Tao Shao-Ming Fei 《International Journal of Theoretical Physics》2016,55(2):886-891
The mutually unbiasedness between a maximally entangled basis (MEB) and an unextendible maximally entangled system (UMES) in the bipartite system \(\mathbb {C}^{2}\otimes \mathbb {C}^{2^{k}} (k>1)\) are introduced and discussed first in this paper. Then two mutually unbiased pairs of a maximally entangled basis and an unextendible maximally entangled system are constructed; lastly, explicit constructions are obtained for mutually unbiased MEB and UMES in \(\mathbb {C}^{2}\otimes \mathbb {C}^{4}\) and \(\mathbb {C}^{2}\otimes \mathbb {C}^{8}\), respectively. 相似文献
3.
We describe s-wave collisions between ultracold 23Na and 87Rb atoms in the presence of a magnetic field. For any collision input channel knowledge of the singlet and triplet intermolecular potentials [1] enables us to predict the variation in scattering lengths as a function of the magnetic field. We employ the Born-Oppenheimer approximation to predict several Feshbach resonances for 23Na87Rb. We also include a discussion of why these resonances are expected to be narrow as observed in the case of 87Rb2.Received: 6 August 2004, Published online: 23 November 2004PACS:
34.90. + q Other topics in atomic collisions - 03.75.Hh Multicomponent condensates 相似文献
4.
It is proved that if any ${\mathbb{Z}}$ -graded weak module for vertex operator algebra V is completely reducible, then V is rational and C 2-cofinite. That is, V is regular. This gives a natural characterization of regular vertex operator algebras. 相似文献
5.
Rani Saroj Verma Ram Krishna Prakash Om 《International Journal of Theoretical Physics》2021,60(4):1299-1327
International Journal of Theoretical Physics - Let $\mathbb {F}_{p^{m}}$ be a finite field with pm elements for an odd prime p and a positive integer m. In this paper, we aim to construct... 相似文献
6.
Domenico Fiorenza Domenico Monaco Gianluca Panati 《Communications in Mathematical Physics》2016,343(3):1115-1157
We consider a gapped periodic quantum system with time-reversal symmetry of fermionic (or odd) type, i.e. the time-reversal operator squares to \({-\mathbb{1}}\). We investigate the existence of periodic and time-reversal invariant Bloch frames in dimensions 2 and 3. In 2d, the obstruction to the existence of such a frame is shown to be encoded in a \({\mathbb{Z}_2}\)-valued topological invariant, which can be computed by a simple algorithm. We prove that the latter agrees with the Fu-Kane index. In 3d, instead, four \({\mathbb{Z}_2}\) invariants emerge from the construction, again related to the Fu-Kane-Mele indices. When no topological obstruction is present, we provide a constructive algorithm yielding explicitly a periodic and time-reversal invariant Bloch frame. The result is formulated in an abstract setting, so that it applies both to discrete models and to continuous ones. 相似文献
7.
Hiroki Matui 《Communications in Mathematical Physics》2010,297(2):529-551
We consider
\mathbbZ{\mathbb{Z}}-actions (single automorphisms) on a unital simple AH algebra with real rank zero and slow dimension growth and show that
the uniform outerness implies the Rohlin property under some technical assumptions. Moreover, two
\mathbbZ{\mathbb{Z}}-actions with the Rohlin property on such a C*-algebra are shown to be cocycle conjugate if they are asymptotically unitarily equivalent. We also prove that locally approximately
inner and uniformly outer
\mathbbZ2{\mathbb{Z}^2}-actions on a unital simple AF algebra with a unique trace have the Rohlin property and classify them up to cocycle conjugacy
employing the OrderExt group as classification invariants. 相似文献
8.
We investigate an extended spin ladder with diagonal frustrated exchanges in a wide parameter regime. By representing the
model as a sum of semidefinite positive projection operators, we prove that this model has exactly a dimer ground state. Smoothly
changing parameters may lead the model cover several exactly known models. Starting from this ladder model, we proposed two
two-dimensional net models with exact ground states. The quantum phase transition of the ground state, due to the change of
exchange strengths along perpendicular rungs, is also discussed.
Received 13 October 2002 Published online 27 January 2003
RID="a"
ID="a"e-mail: schen@thphy.uni.duesseldorf.de 相似文献
9.
Joakim Arnlind Martin Bordemann Laurent Hofer Jens Hoppe Hidehiko Shimada 《Communications in Mathematical Physics》2009,288(2):403-429
We introduce C-Algebras of compact Riemann surfaces as non-commutative analogues of the Poisson algebra of smooth functions on . Representations of these algebras give rise to sequences of matrix-algebras for which matrix-commutators converge to Poisson-brackets
as N → ∞. For a particular class of surfaces, interpolating between spheres and tori, we completely characterize (even for the
intermediate singular surface) all finite dimensional representations of the corresponding C-algebras. 相似文献
10.
Yi-yang Song Gui-jun Zhang Ling-shan Xu Yuan-hong Tao 《International Journal of Theoretical Physics》2018,57(12):3785-3794
We study mutually unbiased unextendible maximally entangled bases (MUUMEBs) in bipartite stystem \(\mathbb {C}^{d}\otimes \mathbb {C}^{d + 1}\). By deriving the sufficient and necessary conditions that two MUUMEBs in \(\mathbb {C}^{3}\otimes \mathbb {C}^{4}\) need to satisfy, we first establish two pairs of MUUMEBs in \(\mathbb {C}^{3}\otimes \mathbb {C}^{4}\). Then we present the sufficient and necessary conditions that two MUUMEBs in bipartite system \(\mathbb {C}^{d}\otimes \mathbb {C}^{d + 1}\) need to satisfy, thus generalize the main results of Halqem et al. (Int. J. Theor. Phys. 54(1), 326, 2015). 相似文献
11.
Recently, we have reported photoassociation of laser-cooled Rb and Cs atoms, decay of the RbCs photoassociation resonances
to high levels of the
state, and reexcitation to vibronic levels of the
state [Kerman et al. , Phys. Rev. Lett. 92, 033004; 153001 (2004)]. Considering the reexcitation spectrum, we report here a preliminary analysis of perturbations in
the c state by high levels of the
and low levels of the
state. Mixing with the B state provides the singlet character needed to stimulate decay to v = 0 of the
ground state. We conclude that an experimental procedure that involves photoassociation of laser-cooled atoms, radiative
decay, and stimulated Raman transfer to the ground electronic state is a feasible method for producing translationally, rotationally,
vibrationally and electronically cold RbCs molecules.
Electronic supplementary material to this article is available at and is accessible for authorized users.
Received: 1 September 2004, Published online: 23 November 2004
PACS:
33.80.Ps Optical cooling of molecules; trapping - 34.50.Gb Electronic excitation and ionization of molecules; intermediate
molecular states (including lifetimes, state mixing, etc.) - 33.20.Kf Visible spectra - 34.20.-b Interatomic and intermolecular
potentials and forces, potential energy surfaces for collisions - 33.15.Pw Fine and hyperfine structure
A supplementary table (Tab. I) is only available in electronic form at http: //www.eurphysj.org 相似文献
12.
A two component model of negative U centers coupled with the Fermi sea of itinerant fermions is discussed in connection with high-temperature superconductivity of cuprates, and superfluidity of atomic fermions. We examine the phase transition and the condensed state of this boson-fermion model (BFM) beyond the ordinary mean-field approximation in two and three dimensions. No pairing of fermions and no condensation are found in two-dimensions for any symmetry of the order parameter. The expansion in the strength of the order parameter near the transition yields no linear homogeneous term in the Ginzburg-Landau-Gorkov equation and a zero upper critical field in any-dimensional BFM, which indicates that previous mean-field discussions of the model are flawed. Normal and anomalous Greens functions are obtained diagrammatically and analytically in the condensed state of a simplest version of 3D BFM. A pairing of bosons analogous to the Cooper pairing of fermions is found. There are three coupled condensates in the model, described by the off-diagonal single-particle boson, pair-fermion and pair-boson fields. These results negate the common wisdom that the boson-fermion model is adequately described by the BCS theory at weak coupling.Received: 26 February 2004, Published online: 18 June 2004PACS:
74.20.-z Theories and models of superconducting state - 74.20.Mn Nonconventional mechanisms (spin fluctuations, polarons and bipolarons, resonating valence bond model, anyon mechanism, marginal Fermi liquid, Luttinger liquid, etc.) - 74.20.Rp Pairing symmetries (other than s-wave) - 74.25.Dw Superconductivity phase diagrams 相似文献
13.
Ł Bibrzycki L. Leśniak A. P. Szczepaniak 《The European Physical Journal C - Particles and Fields》2004,34(3):335-344
Results of a new analysis of the K + K- photoproduction at two photon energies,
and
, with a particular emphasis on the S-wave production are presented. We show that the proper treatment of all the helicity components of the S- and P-waves enables one to eliminate the reported discrepancies in the extraction of the S-wave photoproduction cross section from the experimental data.Received: 28 August 2003, Revised: 3 February 2004, Published online: 23 March 2004 相似文献
14.
Large spin systems as given by magnetic macromolecules or two-dimensional spin arrays rule out an exact diagonalization of
the Hamiltonian. Nevertheless, it is possible to derive upper and lower bounds of the minimal energies, i.e. the smallest energies for a given total spin S. The energy bounds are derived under additional assumptions on the topology of the coupling between the spins. The upper
bound follows from “n-cyclicity", which roughly means that the graph of interactions can be wrapped round a ring with n vertices. The lower bound improves earlier results and follows from “n-homogeneity", i.e. from the assumption that the set of spins can be decomposed into n subsets where the interactions inside and between spins of different subsets fulfill certain homogeneity conditions. Many
Heisenberg spin systems comply with both concepts such that both bounds are available. By investigating small systems which
can be numerically diagonalized we find that the upper bounds are considerably closer to the true minimal energies than the
lower ones.
Received 22 October 2002 / Received in final form 4 April 2003 Published online 20 June 2003
RID="a"
ID="a"e-mail: jschnack@uos.de 相似文献
15.
16.
Amorphous Co80-x
Ho
x
B20 alloys were prepared by melt spinning technique and their magnetic properties have been studied. The magnetic compensation occurs at about x=8. Antiferromagnetic coupling between Co and Ho prevails and breaks at relatively high-fields. The mean field theory has been used to explain the temperature dependence of the magnetization. The exchange interactions between Co-Co and Co-Ho atom pairs have been evaluated.Received: 7 June 2003, Published online: 9 September 2003PACS:
75.50.Kj Amorphous and quasicrystalline magnetic materials - 75.30.Et Exchange and superexchange interactionsS. Sayouri: ssayouri@yahoo.com 相似文献
17.
We prove Ornstein-Zernike behaviour in every direction for finite connection functions of bond percolation on ℤ
d
for d≥3 when p, the probability of occupation of a bond, is sufficiently close to 1. Moreover, we prove that equi-decay surfaces are locally
analytic, strictly convex, with positive Gaussian curvature. 相似文献
18.
TaSe3 belongs to a class of low-dimensional materials characterized by the interplay and competition between dimensionality crossover and broken symmetry ground states. A comprehensive study by dc-transport, optical, and angle-resolved photoemission (ARPES) experiments shows that the electronic properties of this compound are strongly anisotropic between the chain and the transverse crystallographic direction. Even though TaSe3 fails to undergo a charge-density-wave (CDW) phase transition, we found evidence for short range order CDW segments, which progressively disappear with decreasing temperature.Received: 27 April 2004, Published online: 23 July 2004PACS:
78.20.-e Optical properties of bulk materials and thin films - 71.30. + h Metal-insulator transitions and other electronic transitions - 71.45.Lr Charge-density-wave systems 相似文献
19.
We investigate the concept of projectively equivariant quantization in the framework of super projective geometry. When the
projective superalgebra
\mathfrakpgl(p+1|q){\mathfrak{pgl}(p+1|q)} is simple, our result is similar to the classical one in the purely even case: we prove the existence and uniqueness of the
quantization except in some critical situations. When the projective superalgebra is not simple (i.e. in the case of
\mathfrakpgl(n|n)\not @ \mathfraksl(n|n){\mathfrak{pgl}(n|n)\not\cong \mathfrak{sl}(n|n)}), we show the existence of a one-parameter family of equivariant quantizations. We also provide explicit formulas in terms
of a generalized divergence operator acting on supersymmetric tensor fields. 相似文献
20.
We consider bond percolation on \({\mathbb {Z}}^d\times {\mathbb {Z}}^s\) where edges of \({\mathbb {Z}}^d\) are open with probability \(p<p_c({\mathbb {Z}}^d)\) and edges of \({\mathbb {Z}}^s\) are open with probability q, independently of all others. We obtain bounds for the critical curve in (p, q), with p close to the critical threshold \(p_c({\mathbb {Z}}^d)\). The results are related to the so-called dimensional crossover from \({\mathbb {Z}}^d\) to \({\mathbb {Z}}^{d+s}\). 相似文献