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We introduce a measure of quantum non-Gaussianity (QNG) for those quantum
states not accessible by a mixture of Gaussian states in terms of quantum
relative entropy. Specifically, we employ a convex-roof extension using all
possible mixed-state decompositions beyond the usual pure-state decompositions.
We prove that this approach brings a QNG measure fulfilling the properties
desired as a proper monotone under Gaussian channels and conditional Gaussian
operations. As an illustration, we explicitly calculate QNG for the noisy

Blind quantum computation (BQC) allows that a client who has limited quantum
abilities can delegate quantum computation to a server who has advanced quantum
technologies but learns nothing about the client's private information. For
example, measurement-based model can guarantee privacy of client's inputs,
quantum algorithms and outputs. However, it still remains a challenge to
directly encrypt quantum algorithms in circuits model. To solve the problem, we

We study the reduced time-evolution of open quantum systems by combining
quantum-information and statistical field theory. Inspired by prior work [EPL
102, 60001 (2013) and Phys. Rev. Lett. 111, 050402 (2013)] we establish the
explicit structure guaranteeing the complete positivity (CP) and
trace-preservation (TP) of the real-time evolution expansion in terms of the
microscopic system-environment coupling.

The toric code is known to be equivalent to free fermions. This paper
presents explicit local unitary transformations that map the $\mathbb{Z}_2$
toric and surface code --- the open boundary equivalent of the toric code ---
to fermions. Through this construction it is shown that the surface code can be
mapped to a set of free fermion modes, while the toric code requires additional
fermionic symmetry operators. Finally, it is demonstrated how the anyonic
statistics of these codes are encoded in the fermionic representations.

We study entanglement of spin degrees of freedom with continuous one in
supersymmetric (SUSY) quantum mechanics. Concurrence is determined by mean
value of spin and is calculated explicitly for SUSY states. We show that
eigenstates of supercharges are maximally entangled. As an example the
entanglement of atom state with photon state and SUSY in Jaynes-Cummings model
are considered.

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

As with any quantum computing platform, semiconductor quantum dot devices
require sophisticated hardware and controls for operation. The increasing
complexity of quantum dot devices necessitates the advancement of automated
control software and image recognition techniques for rapidly evaluating charge
stability diagrams. We use an image analysis toolbox developed in Python to
automate the calibration of virtual gates, a process that previously involved a
large amount of user intervention. Moreover, we show that straightforward

We propose a practical protocol to generate and observe a non-Abelian
geometric phase using a periodically driven Raman process in the hyperfne
ground state manifold of atoms in a dilute ultracold gas. Our analysis is based
upon recent developments and application of Floquet theory to periodically
driven quantum systems. The simulation results show the non-Abelian gauge
transformation and the non-commuting property of the SU(2) transformation
operators. Based on these results, we propose a possible experimental

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