39 research outputs found
Universal spectra of random Lindblad operators
To understand typical dynamics of an open quantum system in continuous time,
we introduce an ensemble of random Lindblad operators, which generate Markovian
completely positive evolution in the space of density matrices. Spectral
properties of these operators, including the shape of the spectrum in the
complex plane, are evaluated by using methods of free probabilities and
explained with non-Hermitian random matrix models. We also demonstrate
universality of the spectral features. The notion of ensemble of random
generators of Markovian qauntum evolution constitutes a step towards
categorization of dissipative quantum chaos.Comment: 6 pages, 4 figures + supplemental materia
Jean-Luc Marion: teologia w horyzoncie daru
Udostępnienie publikacji Wydawnictwa Uniwersytetu Łódzkiego finansowane w ramach projektu „Doskonałość naukowa kluczem do doskonałości kształcenia”. Projekt realizowany jest ze środków Europejskiego Funduszu Społecznego w ramach Programu Operacyjnego Wiedza Edukacja Rozwój; nr umowy: POWER.03.05.00-00-Z092/17-00
Random Lindblad operators obeying detailed balance
We introduce different ensembles of random Lindblad operators , which
satisfy quantum detailed balance condition with respect to the given stationary
state of size , and investigate their spectral properties. Such
operators are known as `Davies generators' and their eigenvalues are real;
however, their spectral densities depend on . We propose different
structured ensembles of random matrices, which allow us to tackle the problem
analytically in the extreme cases of Davies generators corresponding to random
with a non-degenerate spectrum for the maximally mixed stationary
state, . Interestingly, in the latter case the density
can be reasonably well approximated by integrating out the imaginary component
of the spectral density characteristic to the ensemble of random unconstrained
Lindblad operators. The case of asymptotic states with partially degenerated
spectra is also addressed. Finally, we demonstrate that similar universal
properties hold for the detailed balance-obeying Kolmogorov generators obtained
by applying superdecoherence to an ensemble of random Davies generators. In
this way we construct an ensemble of random classical generators with imposed
detailed balance condition
Noise Fingerprints of Fiber Supercontinuum Sources
We present a novel technique for measuring unique ”noise fingerprints” of fiber supercontinuum (SC) sources, revealing a strong dependence of SC relative intensity noise not only on the dispersion of the fiber, but also on its cross-sectional geometry