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We provide an algorithm that uses Bayesian randomized benchmarking in concert

with a local optimizer, such as SPSA, to find a set of controls that optimizes

that average gate fidelity. We call this method Bayesian ACRONYM tuning as a

reference to the analogous ACRONYM tuning algorithm. Bayesian ACRONYM

distinguishes itself in its ability to retain prior information from

experiments that use nearby control parameters; whereas traditional ACRONYM

tuning does not use such information and can require many more measurements as

- Read more about Bayesian ACRONYM Tuning. (arXiv:1902.05940v1 [quant-ph])
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We report on cryogenic coupling of organic molecules to ring microresonators

obtained by looping sub-wavelength waveguides (nanoguides). We discuss

fabrication and characterization of the chip-based nanophotonic elements which

yield resonator finesse in the order of 20 when covered by molecular crystals.

Our observed extinction dips from single molecules reach 22%, consistent with

the expected Purcell enhancements up to 11 folds. Future efforts will aim at

Recent experimental work with silicon qubits has shown that it is possible,

using an inhomogeneous magnetic field, to strongly couple modes of a microwave

resonator to the spin of a single electron trapped in a double quantum dot.

This suggests the possibility of realizing long-range spin-spin interactions

mediated by cavity photons. We present our theoretical calculation of effective

interactions between distant quantum dot spins coupled by a resonator, and

Nonlocality and contextuality are at the root of conceptual puzzles in

quantum mechanics, and are key resources for quantum advantage in

information-processing tasks. Bell nonlocality is best understood as the

incompatibility between quantum correlations and the classical theory of

causality, applied to relativistic causal structure. Contextuality, on the

other hand, is on a more controversial foundation. In this work, I provide a

common conceptual ground between nonlocality and contextuality as violations of

The system of a proton and an electron in an inert and impenetrable spherical

cavity is studied by solving Schr\"{o}dinger equation with the correct boundary

conditions. The differential equation of a hydrogen atom in a cavity is

derived. The numerical results are obtained with the help a power and efficient

few-body method, Gaussian Expansion Method. The results show that the correct

implantation of the boundary condition is crucial for the energy spectrum of

hydrogen in a small cavity.

We propose a theoretical method to enhance the coherent dipole coupling

between two atoms in an optical cavity via parametrically squeezing the cavity

mode. In the present scheme, conditions for coherent coupling are derived in

detail and diverse dynamics of the system can be obtained by regulating system

parameters. In the presence of environmental noise, an auxiliary squeezed field

is employed to suppress, and even completely eliminate the additional noise

Anticrossing behavior between magnons in a non-collinear chiral magnet

Cu$_2$OSeO$_3$ and a two-mode X-band microwave resonator was studied in the

temperature range 5-100K. In the field-induced ferrimagnetic phase, we observed

a strong coupling regime between magnons and two microwave cavity modes with a

cooperativity reaching 3600. In the conical phase, cavity modes are

dispersively coupled to a fundamental helimagnon mode, and we demonstrate that

the magnetic phase diagram of Cu$_2$OSeO$_3$ can be reconstructed from the

Everett's Relative State Interpretation (aka Many Worlds Interpretation) has

gained increasing interest due to the progress understanding the role of

decoherence. In order to fulfill its promise as a realistic description of the

physical world, two postulates are formulated. In short they are 1) for a

system with continuous coordinates $\mathbf x$, discrete variable $j$, and

state $\psi_j(\mathbf x)$, the density $\rho_j(\mathbf x)=|\psi_j(\mathbf

x)|^2$ gives the distribution of the location of the system with the respect to

Atoms in spatially dependent light fields are attracted to local intensity

maxima or minima depending on the sign of the frequency difference between the

light and the atomic resonance. For light fields confined in open high-Q

optical resonators the backaction of the atoms onto the light field generates

dissipative dynamic opto-mechanical potentials, which can be used to cool and

trap the atoms. Extending the conventional case of high field seekers to the

We revisit the calculation of multi-interval modular Hamiltonians for free

fermions using a Euclidean path integral approach. We show how the

multi-interval modular flow is obtained by gluing together the single interval

modular flows. Using this relation, we obtain an exact expression for the

multi-interval modular Hamiltonian and entanglement entropy in agreement with

existing results. An essential ingredient in our derivation is the introduction

of the \emp{modular action}. This determines the non-local field theory