arXiv subjects

Gustavo Montes

Publications and source records attributed to Gustavo Montes.

5 recordsLinked to original sources

arXiv2024

Symmetry operations and Critical Behaviour in Classical to Quantum Stochastic Processes

Recently, a novel construction scheme for generating quantum analogs of classical stochastic processes has been introduced. Here, we use this scheme in order to generate a large class of self-contained quantum extensions of a classical Markov chain process using symmetry operations. We show that the relaxation processes unfold very differently for the different quantum extensions. This is supported by monitoring the coherence, the probability of reaching the equilibrium, the decay of the number of domain walls and the purity. Unexpectedly, we find a rather ambiguous relation between the coherence measure based on the L1-norm and the speed of the relaxation process. Finally we find that the finite size scaling of the coherence measure exists for both short and long times and the value of the critical exponent is different for the short and long time.

quant-ph↗

arXiv2024

Probing entanglement of a continuous basis system

In this paper, we propose a method to probe entanglement in a theoretically inaccessible quantum system with either a discrete or continuous basis. Our approach leverages insights into the entanglement distribution within a four-partite quantum system, comprising two qubit-oscillator subsystems with dephasing interactions between each qubit-oscillator pair. The method involves measurements applied only to the accessible two-qubit subsystem, enabling a qualitative detection and characterization of quantum correlations in the inaccessible two-oscillator subsystem. This approach provides a novel framework for probing entanglement in continuous-basis systems where traditional measures are often inapplicable due to their complexity. Our findings also reveal an intriguing conservative flow-like behavior in the redistribution of entanglement among subsystems, suggesting that entanglement may exhibit conservative properties in pure composite quantum systems.

quant-ph↗

arXiv2022

From Classical to quantum stochastic process

In this paper for the first time, we construct quantum analogs starting from classical stochastic processes, by replacing random which path decisions with superpositions of all paths. This procedure typically leads to non-unitary quantum evolution, where coherences are continuously generated and destroyed. In spite of their transient nature, these coherences can change the scaling behavior of classical observables. Using the zero temperature Glauber dynamics in a linear Ising spin chain, we find quantum analogs with different domain growth exponents. In some cases, this exponent is even smaller than for the original classical process, which means that coherence can play an important role to speed up the relaxation process.

cond-mat.stat-mech↗

arXiv2015

About Factorization of Quantum States with Few Qubits

We study the factorization conditions of a wave function made up of states of two, three and four qubits and propose and analytical expression which can characterize entangled states in terms of the coefficients of the wave function and density matrix elements.

quant-ph↗

arXiv2015

Study of decoherence of entangled states made up of two basic states in a linear chain of three qubits

Using Lindblad approach to study decoherence of quantum systems, we study the decoherence and decay of entangled states, formed by two basic states of a chain of thee qubits. We look on these states for a possible regular dependence on their decay as a function of their energy separation between the basic states under different type of environments. We found not regular or significant dependence on this energy separation for the type of environment considered .

quant-ph↗