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1.
We investigate the thermal quantum and total correlations in the anisotropic XY spin chain in transverse field. While we adopt concurrence and geometric quantum discord to measure quantum correlations, we use measurement-induced non-locality and an alternative quantity defined in terms of Wigner–Yanase information to quantify total correlations. We show that the ability of these measures to estimate the critical point at finite temperature strongly depend on the anisotropy parameter of the Hamiltonian. We also identify a correlation measure which detects the factorized ground state in this model. Furthermore, we study the effect of temperature on long-range correlations.  相似文献   

2.
We consider energy transfer in polymers in dilute solutions and model it as a purely incoherent, hopping exciton motion which ends at permanent traps, whose positions along the polymer chain are fixed. The transport involves not only steps along the chain but also steps between sites which are far away along the chain's backbone but near to each other in Euclidean space. This possibility leads to very peculiar features of the excitation’s diffusion along the chain, due to strong correlations between subsequent steps. The process depends strongly on whether the chain is frozen or moves. We show that conformational changes influence trapping strongly, even if they are relatively slow on the time scale of the hopping motion. Presented at the Czech-Israeli-German Symposium “Dynamical Processes in Condensed Molecular Systems”, Prague, Czech Republic, 26–30 May 1997.  相似文献   

3.
We study the global and local regularity properties of random wavelet series whose coefficients exhibit correlations given by a tree-indexed Markov chain. We determine the law of the spectrum of singularities of these series, thereby performing their multifractal analysis. We also show that almost every sample path displays an oscillating singularity at almost every point and that the points at which a sample path has at most a given Hölder exponent form a set with large intersection.  相似文献   

4.
We report temperature and magnetic field dependent magnetization and quantification of entanglement from the experimental data for dichloro (thiazole) copper (II), a Heisenberg spin chain system. The plot of magnetic susceptibility vs. temperature indicates an infinite spin chain. Isothermal magnetization measurements (as functions of magnetic field) were performed at various temperatures below the antiferromagnetic (AFM) ordering, where the AFM correlations persist significantly. These magnetization curves are fitted to the Bonner–Fisher model. Magnetic susceptibility is used as an entanglement witness to quantify the amount of entanglement in the system.  相似文献   

5.
The question of whether or not DNA is intrinsically conducting is still a challenge. The ongoing debate on DNA molecules as an electronic material has so far underestimated a key distinction of the system: the role of base pairing in opposition to correlations along each chain. We show that a disordered base paired double chain presents truly or, at least, effectively delocalized states. This effect is irrespective to the sequencing along each chain.  相似文献   

6.
We study the non-equilibrium time evolution of the average transverse magnetisation and end-to-end correlation functions of the random Ising quantum chain. Starting with fully magnetised states, either in the x or z direction, we compute numerically the average quantities. They show similar behaviour to the homogeneous chain, that is an algebraic decay in time toward a stationary state. During the time evolution, the spatial correlations, measured from one end to the other of the chain, are building up and finally at long time they reach a size-dependent constant depending on the distance from criticality. Analytical arguments are given which support the numerical results. Received 11 July 2002 / Received in final form 9 September 2002 Published online 29 October 2002  相似文献   

7.
一维长程关联无序系统中的电子态   总被引:1,自引:0,他引:1       下载免费PDF全文
利用傅里叶滤波法在一维Anderson无序系统中产生了具有幂律谱密度公式s(q)∝q-p形式的长程关联随机能量序列,并利用传输矩阵方法计算了系统中引入了长程关联后的局域长度,同时应用负本征值理论对系统中的电子态密度进行了分析,并分别把计算结果与系统中不具有长程关联时的局域长度与电子态密度进行了比较.结果表明,长程幂律关联的引入对电子态的性质产生了很大的影响,当关联指数p≥2.0时,在系统能带中心范围内发生了部分局域态向退局域态的转变,而同时电子态密度也发生了很大的变化,出现了六个范霍夫奇点,系统的能带范围也相应地得到展宽. 关键词: 无序系统 长程关联 局域长度 电子态密度  相似文献   

8.
郭子政 《中国物理快报》2008,25(3):1079-1082
By using the measure of concurrence, the entanglement of the ground state in the one-dimensional Anderson model is studied with consideration of the long-range correlations. Three kinds of correlations are discussed. We compare the effects of the long-rang Gaussian and power-law correlations between the site energies on the concurrence, and demonstrate the existence of the band structure of the concurrence in the power-law case. The emergence of the sharp kink on the concurrence curve shown in the intraband or in the interband indicates the position at which the localization extent of the state may have the severe variation. We use the Rudin-Shapiro model to describe the site energy distribution of the nucleotides of the DNA chain: guanine (G), adenine (A), cytosine(C), thymine (T). This model is a tetradic quasiperiodic sequence and is shown to be long-range correlated. Our results show that correlations between the site energies increase the concurrences.  相似文献   

9.
We consider the electric double layer formed near the boundary of a weakly nonideal multicomponent classical plasma as a result of interparticle correlations. On the basis of the generalized plasma uncoupling of the equilibrium chain of BBGKY equations, which correctly takes into account correlations of particles at small distances, we find the two-particle and one-particle correlation functions near the surface of the plasma. The asymptotic form of the two-particle correlation function along the boundary of the plasma falls off as the power law 1/r3. The solution obtained here is qualitatively consistent with earlier results, but it takes into account particle correlations at small distances and hence does not have a singularity at the boundary of the plasma. Therefore in a charge-asymmetric plasma there are two correlation radii, the Debye radius D and the radius /tr2D. The thermodynamic functions of the surface layer are calculated.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 3, pp. 72–77, March, 1989.  相似文献   

10.
We prove to all orders of renormalized perturbative polymer field theory the existence of a short chain expansion applying to polymer solutions of long and short chains. For a general polymer network with long and short chains we show factorization of its partition sum by a short chain factor and a long chain factor in the short chain limit. This corresponds to an expansion for short distance along the fractal perimeter of the polymer chains connecting the network vertices and is related to a large mass expansion of field theory.

The scaling of the second virial coefficient for bimodal solutions is explained. Our method also applies to the correlations of the multifractal measure of harmonic diffusion onto an absorbing polymer. We give a result for expanding these correlations for short distance along the fractal carrier of the measure.  相似文献   


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