Many-body localization is shown to suppress imaginary parts of complex
eigenenergies for general non-Hermitian Hamiltonians having time-reversal
symmetry. We demonstrate that a real-complex transition, which we conjecture
occurs upon many-body localization, profoundly affects the dynamical stability
of non-Hermitian interacting systems with asymmetric hopping that respect
time-reversal symmetry. Moreover, the real-complex transition is shown to be
absent in non-Hermitian many-body systems with gain and/or loss that breaks

The theory of quantum thermodynamics investigates how the concepts of heat,
work, and temperature can be carried over to the quantum realm, where
fluctuations and randomness are fundamentally unavoidable. Of particular
practical relevance is the investigation of quantum thermal machines: Machines
that use the flow of heat in order to perform some useful task. In this
lectures series, we give a brief introduction into how the laws of
thermodynamics arise from quantum theory and how thermal machines can be

Suppressing undesired nonunitary effects is a major challenge in quantum
computation and quantum control. In this work, by considering the adiabatic
dynamics in presence of a surrounding environment, we theoretically and
experimentally analyze the robustness of adiabaticity in open quantum systems.
More specifically, by considering a decohering scenario, we exploit the
validity conditions of the adiabatic approximation as well as its sensitiveness
to the resonance situation, which typically harm adiabaticity in closed

We cast diffraction-based interferometry in the framework of post-selected
unitary description towards enabling it as a platform for quantum information
processing. We express slit-diffraction as an infinite-dimensional
transformation and truncate it to a finite-dimensional transfer matrix by
post-selecting modes. Using such a framework with classical fields, a
customized double-slit setup is effectively a lossy beam splitter in a
post-selected sense. Diffraction optics provides a robust alternative to

Alkali-metal-vapor magnetometers, using coherent precession of polarized
atomic spins for magnetic field measurement, have become one of the most
sensitive magnetic field detectors. Their application areas range from
practical uses such as detections of NMR signals to fundamental physics
research such as searches for permanent electric dipole moments. One of the
main noise sources of atomic magnetometers comes from the light shift that
depends on the frequency of the pump laser. In this work, we theoretically

We derive an equation for the time evolution of the natural occupation
numbers for fermionic systems with more than two electrons. The evolution of
such numbers is connected with the symmetry-adapted generalized Pauli exclusion
principle, as well as with the evolution of the natural orbitals and a set of
many-body relative phases. We then relate the evolution of these phases to a
geometrical and a dynamical term, attached to each one of the Slater
determinants appearing in the configuration-interaction expansion of the wave

Bell's theorem implies that any completion of quantum mechanics which uses
hidden variables (that is, preexisting values of all observables) must be
nonlocal in the Einstein sense. This customarily indicates that knowledge of
the hidden variables would permit superluminal communication. Such superluminal
signaling, akin to the existence of a preferred reference frame, is to be
expected. However, here we provide a protocol that allows an observer with
knowledge of the hidden variables to communicate with her own causal past,

Topological edge states arise in parity-time ($\mathcal{PT}$)-symmetric
non-unitary quantum dynamics but have so far only been discussed in the
$\mathcal{PT}$-symmetry-unbroken regime. Here we report the experimental
detection of robust topological edge states in one-dimensional photonic quantum
walks with spontaneously broken $\mathcal{PT}$ symmetry, thus establishing the
existence of topological phenomena therein. We theoretically prove and
experimentally confirm that the global Berry phase in non-unitary quantum-walk

Motivated by recent developments in the realm of matter waves, we explore the
potential of creating solitary waves on the surface of a torus. This is an
intriguing perspective due to the role of curvature in the shape and dynamics
of the coherent structures. We find different families of bright solitary waves
for attractive nonlinearities including ones localized in both angular
directions, as well as waves localized in one direction and homogeneous in the
other. The waves localized in both angular directions have also been

We quantitatively assess the energetic cost of several well-known control
protocols that achieve a finite time adiabatic dynamics, namely counterdiabatic
and local counterdiabatic driving, optimal control, and inverse engineering. By
employing a cost measure based on the norm of the total driving Hamiltonian, we
show that a hierarchy of costs emerges that is dependent on the protocol
duration. As case studies we explore the Landau-Zener model, the quantum
harmonic oscillator, and the Jaynes-Cummings model and establish that