631 research outputs found
Decoherence Effects in a Three-Level System under Gaussian Process
When subjected to a classical fluctuating field characterized by a Gaussian
process, we examine the {purity} and coherence protection in a three-level
quantum system. This symmetry of the three-level system is examined when the
local random field is investigated further in the noiseless and noisy regimes.
In~particular, we consider fractional Gaussian, Gaussian, Ornstein--Uhlenbeck,
and~power law noisy regimes. We show that the destructive nature of the
Ornstein--Uhlenbeck noise toward the symmetry of the qutrit to preserve encoded
{purity and coherence} remains large. Our findings suggest that properly
adjusting the noisy parameters to specifically provided values can facilitate
optimal extended {purity and coherence} survival. Non-vanishing terms appear in
the final density matrix of the single qutrit system, indicating that it is in
a strong coherence regime. Because~of all of the Gaussian noises, monotonic
decay with no revivals has been observed in the single qutrit system. In~terms
of coherence and information preservation, we find that the current qutrit
system outperforms systems with multiple qubits or qutrits using purity and von
Neumann entropy. A~comparison of noisy and noiseless situations shows that the
fluctuating nature of the local random fields is ultimately lost when
influenced using the classical Gaussian noise
Ergodicity bounds for stable Ornstein-Uhlenbeck systems in Wasserstein distance with applications to cutoff stability
This article establishes cutoff stability also known as abrupt thermalization
for generic multidimensional Hurwitz stable Ornstein-Uhlenbeck systems with
(possibly degenerate) L\'evy noise at fixed noise intensity. The results are
based on several ergodicity quantitative lower and upper bounds some of which
make use of the recently established shift linearity property of the
Wasserstein-Kantorovich-Rubinstein distance by the authors. It covers such
irregular systems like Jacobi chains and more general networks of coupled
harmonic oscillators with a heat bath (including L\'evy excitations) at
constant temperature on the outer edges and the so-called Brownian gyrator.Comment: 29 pages, 3 figure
Langevin diffusion in holographic backgrounds with hyperscaling violation
In this note we consider a relativistic heavy quark which moves in the
quark-gluon plasmas. By using the holographic methods, we analyze the Langevin
diffusion process of this relativistic heavy quark. This heavy quark is
described by a trailing string attached to a flavor brane and moving at
constant velocity. The fluctuations of this string are related to the thermal
correlators and the correlation functions are precisely the kinds of objects
that we compute in the gravity dual picture. We obtain the action of the
trailing string in hyperscaling violation backgrounds and we then find the
equations of motion. These equations lead us to construct the Langevin
correlator which helps us to obtain the Langevin constants. Using the Langevin
correlators we derive the densities spectral and simple analytic expressions in
the small and large frequency limits. We examine our works for planar and
-charged black holes with hyperscaling violation and find new constraints on
in the presence of velocity
Cutoff Thermalization for Ornstein-Uhlenbeck Systems with Small Levy Noise in the Wasserstein Distance : Cutoff Thermalization for Ornstein–Uhlenbeck Systems...
This article establishes cutoff thermalization (also known as the cutoff phenomenon) for a class of generalized Ornstein-Uhlenbeck systems with small additive LĂ©vy noise and any nonzero initial value.Peer reviewe
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