We study the steady state entanglement and correlations of an open system

comprised of two fermions coupling with the equilibrium or nonequilibrium

environments. We find that for equilibrium case, quantum correlations exhibit

non-monotonic behavior with the increase of temperature and quantum

entanglement dies at finite temperature. Under nonequilibrium environments, the

quantum correlations can show monotonic or non-monotonic behavior upon the

change of temperature or chemical potential bias depending on the tunneling

# All

Great advances in precision quantum measurement have been achieved with

trapped ions and atomic gases at the lowest possible temperatures. These

successes have inspired ideas to merge the two systems. In this way one can

study the unique properties of ionic impurities inside a quantum fluid or

explore buffer gas cooling of the trapped ion quantum computer. Remarkably, in

spite of its importance, experiments with atom-ion mixtures remained firmly

confined to the classical collision regime. We report a collision energy of

The study of quantum dynamics featuring memory effects has always been a

topic of interest within the theory of open quantum system, which is concerned

about providing useful conceptual and theoretical tools for the description of

the reduced dynamics of a system interacting with an external environment.

Definitions of non-Markovian processes have been introduced trying to capture

the notion of memory effect by studying features of the quantum dynamical map

providing the evolution of the system states, or changes in the

We consider a continuous-time quantum walk on a triple graph and investigate

the influence of the side chain on the propagation in the main chain.

Calculating the interchange of the probabilities between the two parts of the

main chain, we find that a switching effect appears if there are odd number of

points on the side chain when concrete conditions between the length of the

main chain and the position of the side chain are satisfied. Whereas, such an

The realization of the strong coupling regime is requisite for implementing

quantum information tasks. Here, a method for enhancing the atom-field coupling

in highly dissipative coupled cavities is proposed. By introducing parametric

squeezing into the primary cavity which is only virtually excited under

specific parametric conditions, coupling enhancement between atom and auxiliary

cavity is realized for proper squeezing parameters. This enables the system to

We investigate the patterns in distributions of localizable entanglement over

a pair of qubits for random multi-qubit pure states. We observe that the mean

of localizable entanglement increases gradually with increasing the number of

qubits of random pure states while the standard deviation of the distribution

decreases. The effects on the distributions, when the random pure multi-qubit

states are subjected to local as well as global noisy channels, are also

investigated. Unlike the noiseless scenario, the average value of the

We investigate the computational hardness of spin-glass instances on a square

lattice, generated via a recently introduced tunable and scalable approach for

planting solutions. The method relies on partitioning the problem graph into

edge-disjoint subgraphs, and planting frustrated, elementary subproblems that

share a common local ground state, which guarantees that the ground state of

the entire problem is known a priori. Using population annealing Monte Carlo,

We report on a highly controllable, hybrid quantum system consisting of cold

Rydberg atoms and an optical nanofiber interface. Using a two-photon excitation

process to drive $5S \rightarrow 5P \rightarrow 29D $ transitions in $^{87}$Rb,

we observe both coherent and incoherent excitation of the Rydberg atoms at

submicron distances from the fiber surface. The $5S \rightarrow 5D$ transition

is mediated by the cooling laser at 780 nm, while the $5D \rightarrow 29D$

Helium nanodroplets doped with polar molecules are studied by electrostatic

deflection. This broadly applicable method allows even polyatomic molecules to

attain sub-Kelvin temperatures and nearly full orientation in the field. The

resulting intense force from the field gradient strongly deflects even droplets

with tens of thousands of atoms, the most massive neutral systems studied by

beam "deflectometry." We use the deflections to extract droplet size

distributions. Moreover, since each host droplet deflects according to its

Out-of-time-ordered correlators (OTOCs) have been proposed as a tool to

witness quantum information scrambling in many-body system dynamics. These

correlators can be understood as averages over nonclassical multi-time

quasi-probability distributions (QPDs). These QPDs have more information, and

their nonclassical features witness quantum information scrambling in a more

nuanced way. However, their high dimensionality and nonclassicality make QPDs

challenging to measure experimentally. We focus on the topical case of a