Kernel-based support vector machines (SVMs) are supervised machine learning
algorithms for classification and regression problems. We present a method to
train SVMs on a D-Wave 2000Q quantum annealer and study its performance in
comparison to SVMs trained on conventional computers. The method is applied to
both synthetic data and real data obtained from biology experiments. We find
that the quantum annealer produces an ensemble of different solutions that

Diamond-based microelectromechanical systems (MEMS) enable direct coupling
between the quantum states of nitrogen-vacancy (NV) centers and the phonon
modes of a mechanical resonator. One example, diamond high-overtone bulk
acoustic resonators (HBARs), feature an integrated piezoelectric transducer and
support high-quality factor resonance modes into the GHz frequency range. The
acoustic modes allow mechanical manipulation of deeply embedded NV centers with

We present OpenMP versions of C and Fortran programs for solving the
Gross-Pitaevskii equation for a rotating trapped Bose-Einstein condensate (BEC)
in two (2D) and three (3D) spatial dimensions. The programs can be used to
generate vortex lattices and study dynamics of rotating BECs. We use the
split-step Crank-Nicolson algorithm for imaginary- and real-time propagation to
calculate stationary states and BEC dynamics, respectively. The programs
propagate the condensate wave function and calculate several relevant physical

The spatial formation of coherent random laser modes in strongly scattering
disordered random media is a central feature in the understanding of the
physics of random lasers. We derive a quantum field theoretical method for
random lasing in disordered samples of complex amplifying Mie resonators which
is able to provide self-consistently and free of any fit parameter the full set
of transport characteristics at and above the laser phase transition. The
coherence length and the correlation volume respectively is derived as an

Periodic driving can be used to coherently control the properties of a
many-body state and to realize new phases which are not accessible in static
systems. For example, exposing materials to intense laser pulses enables to
provoke metal-insulator transitions, control the magnetic order and induce
transient superconducting behaviour well above the static transition
temperature. However, pinning down the responsible mechanisms is often
difficult, since the response to irradiation is governed by complex many-body

For a bipartite entangled state shared by two observers, Alice and Bob, Alice
can affect the post-measured states left to Bob by choosing different
measurements on her half. Alice can convince Bob that she has such an ability
if and only if the unnormalized postmeasured states cannot be described by a
local-hidden-state (LHS) model. In this case, the state is termed steerable
from Alice to Bob. By converting the problem to construct LHS models for
two-qubit Bell diagonal states to the one for Werner states, we obtain the

Schur-Weyl duality is a ubiquitous tool in quantum information. At its heart
is the statement that the space of operators that commute with the tensor
powers of all unitaries is spanned by the permutations of the tensor factors.
In this work, we describe a similar duality theory for tensor powers of
Clifford unitaries. The Clifford group is a central object in many subfields of
quantum information, most prominently in the theory of fault-tolerance. The
duality theory has a simple and clean description in terms of finite

Recent advances in quantum technology facilitate the realization of
information processing using quantum computers at least on the small and
intermediate scales of up to several dozens of qubits. We investigate
entanglement cost required for one-shot quantum state merging, aiming at
quantum state transformation on these scales. In contrast to existing coding
algorithms achieving nearly optimal approximate quantum state merging on a
large scale, we construct algorithms for exact quantum state merging so that

In quantum theory, the no-information-without-disturbance and
no-free-information theorems express that those observables that do not disturb
the measurement of another observable and those that can be measured jointly
with any other observable must be trivial, i.e., coin tossing observables. We
show that in the framework of general probabilistic theories these statements
do not hold in general and continue to completely specify these two classes of
observables. In this way, we obtain characterizations of the probabilistic

We investigate a temporal evolution of an impurity atom in a one-dimensional
trapped Bose gas following a sudden change of the boson-impurity interaction
strength. Our focus is on the effects of inhomogeneity due to the harmonic
confinement. These effects can be described by an effective one-body model
where both the mass and the spring constant are renormalized. This is in
contrast to the classic renormalization, which addresses only the mass. We
propose an effective single-particle Hamiltonian and apply the multi-layer