Search results for "Statistical physics"
showing 10 items of 1402 documents
Probing Quantum Frustrated Systems via Factorization of the Ground State
2009
The existence of definite orders in frustrated quantum systems is related rigorously to the occurrence of fully factorized ground states below a threshold value of the frustration. Ground-state separability thus provides a natural measure of frustration: strongly frustrated systems are those that cannot accommodate for classical-like solutions. The exact form of the factorized ground states and the critical frustration are determined for various classes of nonexactly solvable spin models with different spatial ranges of the interactions. For weak frustration, the existence of disentangling transitions determines the range of applicability of mean-field descriptions in biological and physica…
Governing Survival Probability to Distill Quantum States
2005
A quantum system interacting with a repeatedly measured one undergoes a nonunitary time evolution pushing it into some specific subspaces. We deeply investigate the origin of the relevant selection rule, bringing to the light its connection with the survival probability related with the two-system interaction. The possibility of inducing an effective dynamics in the distilled subspace just during the distillation process is demonstrated.
Activating remote entanglement in a quantum network by local counting of identical particles
2019
Quantum information and communication processing within quantum networks usually employs identical particles. Despite this, the physical role of quantum statistical nature of particles in large-scale networks remains elusive. Here, we show that just the indistinguishability of fermions makes it possible a new mechanism of entanglement transfer in many-node quantum networks. This process activates remote entanglement among distant sites, which do not share a common past, by only locally counting identical particles and classical communication. These results constitute the key achievement of the present technique and open the way to a more stable multistage transfer of nonlocal quantum correl…
Robust entanglement preparation through spatial indistinguishability quantified by entropic measure
2021
Initialization of composite quantum systems into highly entangled states is important to enable their use for quantum technologies. However, unavoidable noise in the preparation stage makes the system state mixed, hindering the achievement of this goal. We address this problem in the context of identical particle systems adopting the operational framework of spatially localized operations and classical communication (sLOCC). After a brief description of the formalism, we define the entanglement of formation for an arbitrary state (pure or mixed) of two identical qubits, valid for both bosons and fermions. We then introduce an entropic measure of spatial indistinguishability as an informatio…
Probabilities in nonorthogonal basis: Four--quark systems
2009
Four-quark states may exist as colorless meson-meson molecules or compact systems with two-body colored components. We derive an analytical procedure to expand an arbitrary four-quark wave function in terms of nonorthogonal color singlet-singlet vectors. Using this expansion we develop the necessary formalism to evaluate the probability of physical components with an arbitrary four-quark wave function. Its application to characterize bound and unbound four-quark states as meson-meson, molecular, or compact systems is discussed
Shock phenomena in baryonless strongly interacting matter.
1987
Shock phenomena associated with the quark-to-hadron matter phase transition are studied using the concept of adiabats. To allow for an analysis of a medium with vanishing baryon density, the shock and Poisson adiabats are formulated in terms of hydrodynamic fluxes, rather than only thermodynamic variables. The bag-model equation of state is used to describe the phase transition. It is shown that deflagrations from the quark phase above the critical temperature and strong detonations from the supercooled quark phase to the superheated hadron phase are unlikely. Instead the possibility of weak condensation detonations from the supercooled quark phase to a mixed phase is indicated. Strong deto…
Three-particle correlations in QCD jets and beyond
2011
In this paper, we present a more detailed version of our previous work for three-particle correlations in quark and gluon jets [1]. We give theoretical results for this observable in the double logarithmic approximation and the modified leading logarithmic approximation. In both resummation schemes, we use the formalism of the generating functional and solve the evolution equations analytically from the steepest descent evaluation of the one-particle distribution. In addition, in this paper we include predictions beyond the limiting spectrum approximation and study this observable near the hump of the single inclusive distribution. We thus provide a further test of the local parton hadron d…
Formation of Ordered Structures in Quenching Experiments: Scaling Theory and Simulations
1987
In this note we want to address the particular problem of the formation of ordered structures resulting from “quenching experiments”. The generic experimental situation is depicted in Figure 1. Initially the system is in an unordered random state in the one-phase region. Then the temperature is lowered (for some systems like polymers the coexistence curve is inverted so that the temperature must be raised) until the system is in the two phase region. The system is now in a non-equilibrium situation and evolves toward equilibrium. It is during the evolution toward equilibrium that the system develops ordered structures /1,2/.
Queuing transitions in the asymmetric simple exclusion process
2003
Stochastic driven flow along a channel can be modeled by the asymmetric simple exclusion process. We confirm numerically the presence of a dynamic queuing phase transition at a nonzero obstruction strength, and establish its scaling properties. Below the transition, the traffic jam is macroscopic in the sense that the length of the queue scales linearly with system size. Above the transition, only a power-law shaped queue remains. Its density profile scales as $\delta \rho\sim x^{-\nu}$ with $\nu={1/3}$, and $x$ is the distance from the obstacle. We construct a heuristic argument, indicating that the exponent $\nu={1/3}$ is universal and independent of the dynamic exponent of the underlying…
Evolutionary Spectrum for Random Field and Missing Observations
2012
There are innumerable situations where the data observed from a non-stationary random field are collected with missing values. In this work a consistent estimate of the evolutionary spectral density is given where some observations are randomly missing.