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QUROPE - aggregated feeds in category PhysicsenPRA: Quantum information: Quantum-assisted Gaussian process regression
http://link.aps.org/doi/10.1103/PhysRevA.99.052331
<p>Author(s): Zhikuan Zhao, Jack K. Fitzsimons, and Joseph F. Fitzsimons</p><p><a href="http://link.aps.org/doi/10.1103/PhysRevA.99.052331">read more</a></p>
Wed, 22 May 2019 12:00:00 +0200PRA: Quantum information: Optimal quantum subsystem codes in two dimensions
http://link.aps.org/doi/10.1103/PhysRevA.99.052333
<p>Author(s): Theodore J. Yoder</p><p><a href="http://link.aps.org/doi/10.1103/PhysRevA.99.052333">read more</a></p>
Wed, 22 May 2019 12:00:00 +0200arXiv.org: Quantum Physics: Probing and dressing magnetic impurities in a superconductor. (arXiv:1905.07412v1 [cond-mat.mes-hall])
http://arxiv.org/abs/1905.07412
<p>We propose a method to probe and control the interactions between an ensemble
of magnetic impurities in a superconductor via microwave radiation. Our method
relies upon the presence of sub-gap Yu-Shiba-Rusinov (YSR) states associated
with the impurities. Depending on the sign of the detuning, radiation generates
either a ferro- or antiferromagnetic contribution to the exchange interaction.
This contribution can bias the statistics of the random exchange constants
stemming from the RKKY interaction.<p><a href="http://arxiv.org/abs/1905.07412">read more</a></p>
Tue, 21 May 2019 23:45:12 +0200arXiv.org: Quantum Physics: Engineering First-Order Quantum Phase Transitions for Weak Signal Detection. (arXiv:1905.07420v1 [quant-ph])
http://arxiv.org/abs/1905.07420
<p>The quantum critical detector (QCD), recently introduced for weak signal
amplification [Opt. Express 27, 10482 (2019)], functions by exploiting high
sensitivity near the critical point of first-order quantum phase transitions.
We contrast the critical behavior of the first-order as well as the
second-order quantum phase transitions (QPTs) in the detector. We find that the
giant sensitivity, which can be utilized for quantum amplification, only exists
in first-order QPTs.<p><a href="http://arxiv.org/abs/1905.07420">read more</a></p>
Tue, 21 May 2019 23:45:12 +0200arXiv.org: Quantum Physics: A topological signature of multipartite entanglement. (arXiv:1905.07454v1 [quant-ph])
http://arxiv.org/abs/1905.07454
<p>Topology and entanglement promise to play a prominent role in understanding
non-local properties of many-body quantum systems. Here, we present a novel
proposal to relate the two and study multipartite entanglement by collecting
statistics of topological invariants of hard-core bosons worldline
configurations in two-dimensional lattices. We build our approach upon the
path-integral formulation of the density matrix in the limit of zero
temperature, and consider worldline configurations, i.e. collections of
particle paths, as geometric braids with a certain topological structure.<p><a href="http://arxiv.org/abs/1905.07454">read more</a></p>
Tue, 21 May 2019 23:45:12 +0200arXiv.org: Quantum Physics: Polynomial Time Algorithms for Estimating Spectra of Adiabatic Hamiltonians. (arXiv:1905.07461v1 [quant-ph])
http://arxiv.org/abs/1905.07461
<p>Much research regarding quantum adiabatic optimization has focused on
stoquastic Hamiltonians with Hamming symmetric potentials, such as the well
studied ``spike" example. Due to the large amount of symmetry in these
potentials such problems are readily open to analysis both analytically and
computationally. However, more realistic potentials do not have such a high
degree of symmetry and may have many local minima. Here we present a somewhat
more realistic class of problems consisting of many individually Hamming
symmetric potential wells.<p><a href="http://arxiv.org/abs/1905.07461">read more</a></p>
Tue, 21 May 2019 23:45:12 +0200arXiv.org: Quantum Physics: The exponential-nonexponential transition in quantum decay as a phenomenon of interference in time domain of the decaying particle with itself. (arXiv:1905.07493v1 [quant-ph])
http://arxiv.org/abs/1905.07493
<p>By using an exact analytical non-Hermitian approach in terms of resonance
(quasinormal) states we express the decaying wave function as the sum of
exponential and nonexponential decaying solutions to the time-dependent
Schr\"odinger equation. We show that the exponential-nonexponential transition
of decay at long times represents physically a process of interference in time
domain of the decaying particle with itself.
</p>Tue, 21 May 2019 23:45:12 +0200arXiv.org: Quantum Physics: Generalized power functions for one-dimensional supersymmetric quantum mechanics. (arXiv:1905.07509v1 [math-ph])
http://arxiv.org/abs/1905.07509
<p>Complex-valued functions defined on a finite interval $[a,b]$ generalizing
power functions of the type $(x-x_0)^n$ for $n\geq 0$ are studied. These
functions called $\Phi$-generalized powers, $\Phi$ being a given nonzero
complex-valued function on the interval, were considered to contruct a general
solution representation of the Sturm-Liouville equation in terms of the
spectral parameter \cite{kravchenko2008, kravporter2010}.<p><a href="http://arxiv.org/abs/1905.07509">read more</a></p>
Tue, 21 May 2019 23:45:12 +0200arXiv.org: Quantum Physics: Geometric Measures of Information for Quantum State Characterization. (arXiv:1905.07520v1 [quant-ph])
http://arxiv.org/abs/1905.07520
<p>We analyze the geometry of a joint distribution over a set of discrete random
variables. We briefly review Shannon's entropy, conditional entropy, mutual
information and conditional mutual information. We review the entropic
information distance formula of Rokhlin and Rajski. We then define an analogous
information area. We motivate this definition and discuss its properties. We
extend this definition to higher-dimensional volumes. We briefly discuss the
potential utility for these geometric measures in quantum information
processing.
</p>Tue, 21 May 2019 23:45:12 +0200arXiv.org: Quantum Physics: Properties of Quantum Reactivity for a Multipartite State. (arXiv:1905.07522v1 [quant-ph])
http://arxiv.org/abs/1905.07522
<p>We discuss the properties of quantum state reactivity as a measure for
quantum correlation. This information geometry-based definition is a
generalization of the two qubit construction of Schumacher to multipartite
quantum states. It requires a generalization of information distance to
information areas as well as to higher-dimensional volumes. The reactivity is
defined in the usual chemistry way as a ratio of surface area to volume. The
reactivity is an average over all detector settings. We show that this measure
posses the key features required for a measure of quantum correlation.<p><a href="http://arxiv.org/abs/1905.07522">read more</a></p>
Tue, 21 May 2019 23:45:12 +0200