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QUROPE - aggregated feeds in category JournalsenarXiv.org: Quantum Physics: Measuring Arbitrary Physical Properties in Analog Quantum Simulation. (arXiv:2212.02517v1 [quant-ph])
http://arxiv.org/abs/2212.02517
<p>A central challenge in analog quantum simulation is to characterize desirable
physical properties of quantum states produced in experiments. However, in
conventional approaches, the extraction of arbitrary information requires
performing measurements in many different bases, which necessitates a high
level of control that present-day quantum devices may not have. Here, we
propose and analyze a scalable protocol that leverages the ergodic nature of
generic quantum dynamics, enabling the efficient extraction of many physical
properties.<p><a href="http://arxiv.org/abs/2212.02517">read more</a></p>
Thu, 08 Dec 2022 00:45:11 +0100arXiv.org: Quantum Physics: Deep quantum neural networks equipped with backpropagation on a superconducting processor. (arXiv:2212.02521v1 [quant-ph])
http://arxiv.org/abs/2212.02521
<p>Deep learning and quantum computing have achieved dramatic progresses in
recent years. The interplay between these two fast-growing fields gives rise to
a new research frontier of quantum machine learning. In this work, we report
the first experimental demonstration of training deep quantum neural networks
via the backpropagation algorithm with a six-qubit programmable superconducting
processor.<p><a href="http://arxiv.org/abs/2212.02521">read more</a></p>
Thu, 08 Dec 2022 00:45:11 +0100arXiv.org: Quantum Physics: Enhancing Quantum Adversarial Robustness by Randomized Encodings. (arXiv:2212.02531v1 [quant-ph])
http://arxiv.org/abs/2212.02531
<p>The interplay between quantum physics and machine learning gives rise to the
emergent frontier of quantum machine learning, where advanced quantum learning
models may outperform their classical counterparts in solving certain
challenging problems. However, quantum learning systems are vulnerable to
adversarial attacks: adding tiny carefully-crafted perturbations on legitimate
input samples can cause misclassifications.<p><a href="http://arxiv.org/abs/2212.02531">read more</a></p>
Thu, 08 Dec 2022 00:45:11 +0100arXiv.org: Quantum Physics: Shadow tomography from emergent state designs in analog quantum simulators. (arXiv:2212.02543v1 [quant-ph])
http://arxiv.org/abs/2212.02543
<p>We introduce a method that allows one to infer many properties of a quantum
state -- including nonlinear functions such as R\'enyi entropies -- using only
global control over the constituent degrees of freedom. In this protocol, the
state of interest is first entangled with a set of ancillas under a fixed
global unitary, before projective measurements are made.<p><a href="http://arxiv.org/abs/2212.02543">read more</a></p>
Thu, 08 Dec 2022 00:45:11 +0100arXiv.org: Quantum Physics: Robustness of Quantum Algorithms for Nonconvex Optimization. (arXiv:2212.02548v1 [quant-ph])
http://arxiv.org/abs/2212.02548
<p>Recent results suggest that quantum computers possess the potential to speed
up nonconvex optimization problems. However, a crucial factor for the
implementation of quantum optimization algorithms is their robustness against
experimental and statistical noises. In this paper, we systematically study
quantum algorithms for finding an $\epsilon$-approximate second-order
stationary point ($\epsilon$-SOSP) of a $d$-dimensional nonconvex function, a
fundamental problem in nonconvex optimization, with noisy zeroth- or
first-order oracles as inputs.<p><a href="http://arxiv.org/abs/2212.02548">read more</a></p>
Thu, 08 Dec 2022 00:45:11 +0100arXiv.org: Quantum Physics: On the Evolution of States in a Quantum-Mechanical Model of Experiments. (arXiv:2212.02599v1 [quant-ph])
http://arxiv.org/abs/2212.02599
<p>The postulates of von Neumann and L\"uders concerning measurements in quantum
mechanics are discussed and criticized in the context of a simple model
proposed by Gisin. The main purpose of our paper is to analyze some
mathematical aspects of that model and to draw some general lessons on the
so-called ``measurement problem'' in quantum mechanics pointing towards the
need to introduce general principles that determine the law for the stochastic
time evolution of states of individual physical systems.
</p>Thu, 08 Dec 2022 00:45:11 +0100arXiv.org: Quantum Physics: Training quantum neural networks using the Quantum Information Bottleneck method. (arXiv:2212.02600v1 [quant-ph])
http://arxiv.org/abs/2212.02600
<p>Information Bottleneck is a concept in classical information theory derived
by Tishby et al. that has been used to study information flow in neural
networks. This approach frames an information processing problem as an
inference problem and tries to quantify how much of the "relevant" information
is retained by the process, relevance here being measured with mutual
information between the input/output and some fixed ground truth.<p><a href="http://arxiv.org/abs/2212.02600">read more</a></p>
Thu, 08 Dec 2022 00:45:11 +0100arXiv.org: Quantum Physics: Errors in stimulated-Raman-induced logic gates in $^{133}$Ba$^+$. (arXiv:2212.02608v1 [quant-ph])
http://arxiv.org/abs/2212.02608
<p>${}^{133}\mathrm{Ba}^+$ is illuminated by a laser that is far-detuned from
optical transitions, and the resulting spontaneous Raman scattering rate is
measured. The observed scattering rate is lower than previous theoretical
estimates. The majority of the discrepancy is explained by a more accurate
treatment of the scattered photon density of states. This work establishes
that, contrary to previous models, there is no fundamental limit to
laser-driven quantum gates from laser-induced spontaneous Raman scattering.
</p>Thu, 08 Dec 2022 00:45:11 +0100arXiv.org: Quantum Physics: Diabatic Quantum Annealing for the Frustrated Ring Model. (arXiv:2212.02624v1 [quant-ph])
http://arxiv.org/abs/2212.02624
<p>Quantum annealing is a continuous-time heuristic quantum algorithm for
solving or approximately solving classical optimization problems. The algorithm
uses a schedule to interpolate between a driver Hamiltonian with an
easy-to-prepare ground state and a problem Hamiltonian whose ground state
encodes solutions to an optimization problem.<p><a href="http://arxiv.org/abs/2212.02624">read more</a></p>
Thu, 08 Dec 2022 00:45:11 +0100arXiv.org: Quantum Physics: Classical Elastic Two-Particle Collision Energy Conservation using Edward Nelson's Energy, Double Diffusion and Special Relativity. (arXiv:2212.02637v1 [quant-ph])
http://arxiv.org/abs/2212.02637
<p>The present paper shows that Edward Nelson's stochastic mechanics approach
for quantum mechanics can be derived from the two classical elastically
colliding particles with masses M and m satisfying a collision momentum
preserving equation. The properties of the classical elastic momentum collision
expression determine the full Edward Nelson energy collision energy for both
particles. This classical total energy expression does not require a
statistical expectation since no process was defined for the energy and it
models the main and incident particle velocities perfectly.<p><a href="http://arxiv.org/abs/2212.02637">read more</a></p>
Thu, 08 Dec 2022 00:45:11 +0100