# All

Arrays of coupled semiconductor lasers are systems possessing complex

dynamical behavior that are of major interest in photonics and laser science.

The onset of dynamical instabilities arising from supermode competition and

slow carrier dynamics is known to prevent stable phase locking in a wide range

of parameter space, requiring special methods to realize stable laser

operation. Inspired by recent concepts of parity-time ($\mathcal{PT}$) and

non-Hermitian photonics, in this work we consider non-Hermitian coupling

- Read more about Non-Hermitian laser phase locking. (arXiv:1802.05439v1 [physics.optics])
- Log in or register to post comments
- 1 read

In [arXiv:1712.03219] the existence of a strongly (pointwise) converging

sequence of quantum channels that can not be represented as a reduction of a

sequence of unitary channels strongly converging to a unitary channel is shown.

In this work we give a simple characterization of sequences of quantum channels

that have the above representation. The corresponding convergence is called the

$*$-strong convergence, since it relates to the convergence of selective

Bragg waveguides are promising optical filters for pump suppression in

spontaneous Four-Wave Mixing (FWM) photon sources. In this work, we investigate

the generation of unwanted photon pairs in the filter itself. We do this by

taking advantage of the relation between spontaneous and classical FWM, which

allows for the precise characterisation of the nonlinear response of the

device. The pair generation rate estimated from the classical measurement is

compared with the theoretical value calculated by means of a full quantum model

In this paper, we introduce quantum fidelity based measurement induced

nonlocality for the bipartite state over two-sided von Neumann projective

measurements. While all the properties of this quantity are reflected from that

of one-sided measurement, the latter one is shown to set an upper bound for

arbitrary bipartite state. As an illustration, we have studied the nonlocality

of Bell diagonal state.

We analytically investigate the recently proposed and implemented

discrete-time quantum walk based on kicked ultra-cold atoms. We show how the

internal level structure of the kicked atoms leads to the emergence of a

relative light-shift phase immediately relevant for the experimental

realization. Analytical solutions are provided for the momentum distribution

for both the case of quantum resonance and the near-resonant quasimomenta.

The core problem in optimal control theory applied to quantum systems is to

determine the temporal shape of an applied field in order to maximize the

expectation of value of some physical observable. The functional which maps the

control field into a given value of the observable defines a Quantum Control

Landscape (QCL). Studying the topological and structural features of these

landscapes is of critical importance for understanding the process of finding

This book is an introduction to quantum Markov chains and explains how this

concept is connected to the question of how well a lost quantum mechanical

system can be recovered from a correlated subsystem. To achieve this goal, we

strengthen the data-processing inequality such that it reveals a statement

about the reconstruction of lost information. The main difficulty in order to

understand the behavior of quantum Markov chains arises from the fact that

- Read more about Approximate quantum Markov chains. (arXiv:1802.05477v1 [quant-ph])
- Log in or register to post comments
- 1 read

The 1-D Anderson model possesses a completely localized spectrum of

eigenstates for all values of the disorder. We consider the effect of

projecting the Hamiltonian to a truncated Hilbert space, destroying time

reversal symmetry. We analyze the ensuing eigenstates using different measures

such as inverse participation ratio and sample-averaged moments of the position

operator. In addition, we examine amplitude fluctuations in detail to detect

the possibility of multifractal behavior (characteristic of mobility edges)

Non-Markovian quantum effects are typically observed in systems interacting

with structured reservoirs. Discrete-time quantum walks are prime example of

such systems in which, quantum memory arises due to the controlled interaction

between the coin and position degrees of freedom. Here we show that the

information backflow that quantifies memory effects can be enhanced when the

particle is subjected to uncorrelated static or dynamic disorder. The presence

of disorder in the system leads to localization effects in 1-dimensional

We study a one-dimensional system of strongly-correlated bosons interacting

with a dynamical lattice. A minimal model describing the latter is provided by

extending the standard Bose-Hubbard Hamiltonian to include extra degrees of

freedom on the bonds of the lattice. We show that this model is capable of

reproducing phenomena similar to those present in usual fermion-phonon models.

In particular, we discover a bosonic analog of the Peierls transition, where