24 research outputs found
Power-law Solutions from Heterotic Strings
In this paper, we search for accelerating power-law and ekpyrotic solutions
in heterotic string theory with NS-NS fluxes compactified on half-flat and
generalized half-flat manifolds. We restrict our searches to the STZ sector of
the theory. We also considered linear order corrections for the
half-flat case. The power-law solutions that we find are neither accelerating
nor ekpyrotic in any of the models.Comment: 21 pages. Major revision. Conclusions change
Renormalized Entanglement Entropy for BPS Black Branes
We compute the renormalized entanglement entropy (REE) for BPS black
solutions in , 4d gauged supergravity. We find that this quantity
decreases monotonically with the size of the entangling region until it reaches
a critical point, then increases and approaches the entropy density of the
brane. This behavior can be understood as a consequence of the REE being driven
by two competing factors, namely entanglement and the mixedness of the black
brane. In the UV entanglement dominates, whereas in the IR the mixedness takes
over.Comment: 6 pages, 4 figures; v2: Typos fixed, citation and clarifying text
added, version accepted in Physical Review
Quantum Spread Complexity in Neutrino Oscillations
Quantum information theory has recently emerged as a flourishing area of
research and quantum complexity, one of its powerful measures, is being applied
for investigating complex systems in many areas of physics. Its application to
practical physical situations, however, is still few and far between. Neutrino
flavor oscillation is a widely studied physical phenomena with far reaching
consequences in understanding the standard model of particle physics and to
search for physics beyond it. Oscillation arises because of mixing between the
flavor and mass eigenstates, and their evolution over time. It is an inherent
quantum system for which flavor transitions are traditionally studied with
probabilistic measures. We have applied quantum complexity formalism as an
alternate measure to study neutrino oscillations. In particular, quantum spread
complexity revealed additional information on the violation of charge-parity
symmetry in the neutrino sector. Our results indicate that complexity favors
the maximum violation of charge-parity, hinted recently by experimental data.Comment: 29 pages, 9 figures, Accepted for publication in Eur. Phys. J.
Towards the Web of Quantum Chaos Diagnostics
We study the connections between three quantities that can be used as
diagnostics for quantum chaos, i.e., the out-of-time-order correlator (OTOC),
Loschmidt echo (LE), and complexity. We generalize the connection between OTOC
and LE for infinite dimensions and extend it for higher-order OTOCs and
multi-fold LEs. Novel applications of this intrinsic relation are proposed. We
also propose a relationship between a specific circuit complexity and LE by
using the inverted oscillator model. These relationships signal a deeper
connection between these three probes of quantum chaos.Comment: 14 pages, 11 figures, 1 appendi
Krylov Complexity and Spectral Form Factor for Noisy Random Matrix Models
We study the spectral properties of two classes of random matrix models:
non-Gaussian RMT with quartic and sextic potentials, and RMT with Gaussian
noise. We compute and analyze the quantum Krylov complexity and the spectral
form factor for both of these models. We find that both models show suppression
of the spectral form factor at short times due to decoherence effects, but they
differ in their long-time behavior. In particular, we show that the Krylov
complexity for the non-Gaussian RMT and RMT with noise deviates from that of a
Gaussian RMT, and provide a physical interpretation of this deviation. We
discuss the implications and limitations of our results for quantum chaos and
quantum information in open quantum systems. Our study reveals the distinct
sensitivities of the spectral form factor and complexity to non-Gaussianity and
noise, which contribute to the observed differences in the different time
domains.Comment: 26 pages, 11 figure