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We apply advanced methods of control theory to open quantum systems and we

determine finite-time processes which are optimal with respect to thermodynamic

performances. General properties and necessary conditions characterizing

optimal drivings are derived, obtaining bang-bang type solutions corresponding

to control strategies switching between adiabatic and isothermal

transformations. A direct application of these results is the maximization of

the work produced by a generic quantum heat engine, where we show that the

In this study, we solve analytically the Schrodinger equation for a

macroscopic quantum oscillator as a central system coupled to a large number of

environmental micro-oscillating particles. Then, the Langevin equation is

obtained for the system using two approaches: Quantum Mechanics and Bohmian

Theory. Our results show that the predictions of the two theories are

inherently different in real conditions. Nevertheless, the Langevin equation

obtained by Bohmian approach could be reduced to the quantum one, when the

PT-symmetric quantum mechanics allows finding stationary states in mean-field

systems with balanced gain and loss of particles. In this work we apply this

method to rotating Bose-Einstein condensates with contact interaction which are

known to support ground states with vortices. Due to the particle exchange with

the environment transport phenomena through ultracold gases with vortices can

be studied. We find that even strongly interacting rotating systems support

Entanglement distribution is a prerequisite for several important quantum

information processing and computing tasks, such as quantum teleportation,

quantum key distribution, and distributed quantum computing. In this work, we

focus on two-dimensional quantum networks based on optical quantum technologies

using dual-rail photonic qubits. We lay out a quantum network architecture for

entanglement distribution between distant parties, with the technological

constraint that quantum repeaters equipped with quantum memories are not

We investigate the use of twin-mode quantum states of light with symmetric

statistical features in their photon number for improving intensity-sensitive

surface plasmon resonance (SPR) sensors. For this purpose, one of the modes is

sent into a prism setup where the Kretschmann configuration is employed as a

sensing platform and the analyte to be measured influences the SPR excitation

conditions. This influence modifies the output state of light that is

subsequently analyzed by an intensity-difference measurement scheme. We show

We report on the existence and stability of freely moving solitons in a

spatially inhomogeneous Bose- Einstein condensate with helicoidal spin-orbit

(SO) coupling. In spite of the periodically varying parameters, the system

allows for the existence of stable propagating solitons. Such states are found

in the rotating frame, where the helicoidal SO coupling is reduced to a

homogeneous one. In the absence of the Zeeman splitting, the coupled

Gross-Pitaevskii equations describing localized states feature many properties

Dynamical decoupling as one of quantum control strategies aimed at

suppressing quantum decoherence adopt the popular philosophy that the disorder

in the unitary evolution of the open quantum system caused by environmental

noises should be neutralized by a sequence of ordered or well-designed external

operations acting on the system. This work studies the exact solution of

quantum-state-diffusion equations by mixing two channels of environmental

noises, i.e., relaxation (dissipation) and dephasing. It is interesting to find

The quantum autoencoder is a recent paradigm in the field of quantum machine

learning, which may enable an enhanced use of resources in quantum

technologies. To this end, quantum neural networks with less nodes in the inner

than in the outer layers were considered. Here, we propose a useful connection

between approximate quantum adders and quantum autoencoders. Specifically, this

link allows us to employ optimized approximate quantum adders, obtained with

genetic algorithms, for the implementation of quantum autoencoders for a

Given an arbitrary quantum state ($\sigma$), we obtain an explicit

construction of a state $\rho^*_\varepsilon(\sigma)$ (resp.

$\rho_{*,\varepsilon}(\sigma)$) which has the maximum (resp. minimum) entropy

among all states which lie in a specified neighbourhood ($\varepsilon$-ball) of

$\sigma$. Computing the entropy of these states leads to a local strengthening

of the continuity bound of the von Neumann entropy, i.e., the Audenaert-Fannes

inequality. Our bound is local in the sense that it depends on the spectrum of

We show that Gibbs states of non-homogeneous transverse Ising chains satisfy

a \emph{shielding} property. Namely, whatever the fields on each spin and

exchange couplings between neighboring spins are, if the field in one

particular site is null, the reduced states of the subchains to the right and

to the left of this site are \emph{exactly} the Gibbs states of each subchain

alone. Therefore, even if there is a strong exchange coupling between the

extremal sites of each subchain, the Gibbs states of the each subchain behave