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The three-state Majorana model in the presence of dissipation is considered.
Different models of system-environment interaction are explored, ranging from
situation where dissipation is the main effect to regimes where dephasing is
mainly produced. It is shown that the detrimental effects of the noise are
stronger in the presence of dissipation than in the presence of dephasing. The
role of temperature is also discussed.

We report a formation of sharp, solitonlike structures in an experimentally
accessible ultracold Fermi gas, as a quantum carpet solution is analyzed in a
many body system. The effect is perfectly coherent in a noninteracting gas, but
in the presence of repulsive interaction in a two-component system, the
structures vanish at a finite time. As they disappear, the system enters a
dynamical equilibrium, in which kinetic energies of atoms tend to the same
average value. The coherence is revived in a strong interaction regime, with

We present an algorithm for learning a latent variable generative model via
generative adversarial learning where the canonical uniform noise input is
replaced by samples from a graphical model. This graphical model is learned by
a Boltzmann machine which learns low-dimensional feature representation of data
extracted by the discriminator. A quantum annealer, the D-Wave 2000Q, is used
to sample from this model. This algorithm joins a growing family of algorithms

In recent years, mono-layers and multi-layers of hexagonal boron nitride
(hBN) have been demonstrated as host materials for localized atomic defects
that can be used as emitters for ultra-bright, non-classical light. The origin
of the emission, however, is still subject to debate. Based on measurements of
photon statistics, lifetime and polarization on selected emitters we find that
these atomic defects do not act as pure single photon emitters. Our results

We consider imperfect two-mode bosonic quantum transducers that cannot
completely transfer an initial source-system quantum state due to insufficient
coupling strength or other non-idealities. We show that such transducers can
generically be made perfect by using interference and phase-sensitive
amplification. Our approach is based on the realization that a particular kind
of imperfect transducer (one which implements a swapped quantum non-demolition
(QND) gate) can be made into a perfect one-way transducer using feed-forward

We propose a generalized Dicke model which supports a quantum tricritical
point. We map out the phase diagram and investigate the critical behaviors of
the model through exact low-energy effective Hamiltonian in the thermodynamic
limit. As predicted by the Landau theory of phase transition, the order
parameter shows non-universality at the tricritical point. Nevertheless, as a
result of the separation of the classical and the quantum degrees of freedom,
we find a universal relation between the excitation gap and the entanglement

The representation of quantum states via phase-space functions constitutes an
intuitive technique to characterize light. However, the reconstruction of such
distributions is challenging as it demands specific types of detectors and
detailed models thereof to account for their particular properties and
imperfections. To overcome these obstacles, we derive and implement a
measurement scheme that enables a reconstruction of phase-space distributions
whose functionality does not depend on the knowledge of the detectors, thus

Nonlinear resonances in the classical phase space lead to a significant
enhancement of tunneling. We demonstrate that the double resonance gives rise
to a complicated tunneling peak structure. Such double resonances occur in
Hamiltonian systems with an at least four-dimensional phase space. To explain
the tunneling peak structure, we use the universal description of single and
double resonances by 4D normal-form Hamiltonians. By applying perturbative
methods, we reveal the underlying mechanism of enhancement and suppression of

Topological insulators are materials that have a gapped bulk energy spectrum,
but contain protected in-gap states appearing at their surface. These states
exhibit remarkable properties such as unidirectional propagation and robustness
to noise that offer an opportunity to improve the performance and scalability
of quantum technologies. For quantum applications, it is essential that the
topological states are indistinguishable. Here we report high-visibility

We discuss phonon-induced non-Markovian and Markovian features in QD-based
optics. We cover lineshapes in linear absorption experiments, phonon-induced
incoherence in the Heitler regime, and memory correlations in two-photon
coherences. To quantitatively and qualitatively understand the underlying
physics, we present several theoretical models which model the non-Markovian
properties of the electron-phonon interaction accurately in different regimes.
Examples are the Heisenberg equation of motion approach, the polaron master