QUROPE aggregator
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QUROPE - aggregated feedsenarXiv.org: Quantum Physics: A Dyson equation approach for averaging of classical and quantum observables on multiple realizations of Markov processes. (arXiv:2004.01183v1 [quant-ph])
http://arxiv.org/abs/2004.01183
<p>Time dependent signals in experimental techniques such as Nuclear Magnetic
Resonance (NMR) and Muon Spin Relaxation (muSR) are often the result of an
ensemble average over many microscopical dynamical processes. While there are a
number of functions used to fit these signals, they are often valid only in
specific regimes, and almost never properly describe the "spectral diffusion"
regime, in which the dynamics happen on time scales comparable to the
characteristic frequencies of the system.<p><a href="http://arxiv.org/abs/2004.01183">read more</a></p>
Mon, 06 Apr 2020 12:54:13 +0200arXiv.org: Quantum Physics: Study of the spin kitten states in a strongly coupled spin-oscillator system. (arXiv:2004.01187v1 [quant-ph])
http://arxiv.org/abs/2004.01187
<p>Utilizing an adiabatic approximation method a bipartite qudit-oscillator
Hamiltonian is explicitly studied for low spin values in both strong and
ultrastrong coupling regimes. The quasiprobability densities on the hybrid
factorized phase space are introduced. Integrating over a sector of the
composite phase space, the quasiprobability distributions of the complementary
subsystem are recovered.<p><a href="http://arxiv.org/abs/2004.01187">read more</a></p>
Mon, 06 Apr 2020 12:54:13 +0200arXiv.org: Quantum Physics: Testing Quantum Gravity with a Single Quantum System. (arXiv:2004.01189v1 [quant-ph])
http://arxiv.org/abs/2004.01189
<p>Until recently, table-top tests of quantum gravity (QG) were thought to be
practically impossible. However, due to a radical new approach to testing QG
that uses principles of quantum information theory (QIT) and quantum
technology, such tests now seem, remarkably, within sight. In particular, a
promising test has been proposed where the generation of entanglement between
two massive quantum systems, both in a superposition of two locations, would
provide evidence of QG. In QIT, quantum information can be encoded in discrete
variables, such as qubits, or continuous variables.<p><a href="http://arxiv.org/abs/2004.01189">read more</a></p>
Mon, 06 Apr 2020 12:54:13 +0200arXiv.org: Quantum Physics: Unveiling the Finite Temperature Physics of Hydrogen Chains via Auxiliary Field Quantum Monte Carlo. (arXiv:2004.01194v1 [cond-mat.str-el])
http://arxiv.org/abs/2004.01194
<p>The ability to accurately predict the finite temperature properties of
realistic quantum solids is central to uncovering new phases and engineering
materials with novel properties. Nonetheless, there remain comparatively few
many-body techniques capable of elucidating the finite temperature physics of
solids from first principles.<p><a href="http://arxiv.org/abs/2004.01194">read more</a></p>
Mon, 06 Apr 2020 12:54:13 +0200arXiv.org: Quantum Physics: Certifying quantum signatures in thermodynamics and metrology via contextuality of quantum linear response. (arXiv:2004.01213v1 [quant-ph])
http://arxiv.org/abs/2004.01213
<p>We give a general test to certify that the quantum phenomenology in the
linear response regime cannot be described by any noncontextual emulator. This
allows us to provide the first proof of a quantum signature in the operation of
a quantum engine certified against generic classical emulations. Furthermore,
we describe contextual advantages for local metrology. Given the ubiquity of
linear response theory, we anticipate that our tools will allow to certify the
absence of classical emulators for a wide array of quantum phenomena.
</p>Mon, 06 Apr 2020 12:54:12 +0200arXiv.org: Quantum Physics: Exponentially enhanced quantum metrology using resources of linear complexity. (arXiv:2004.01216v1 [quant-ph])
http://arxiv.org/abs/2004.01216
<p>The coherent interaction time provides an important type of serial resource
in quantum metrology, where seeking a higher-order time scaling in quantum
Fisher information(QFI) is crucial to achieve better enhancement. In this work,
we investigate a generalized model where the parameter is coupled to only one
part of the total Hamiltonian, making it possible to utilize the
non-commutative property in deriving the expression of QFI.<p><a href="http://arxiv.org/abs/2004.01216">read more</a></p>
Mon, 06 Apr 2020 12:54:12 +0200arXiv.org: Quantum Physics: Supervised Learning with Quantum Measurements. (arXiv:2004.01227v1 [quant-ph])
http://arxiv.org/abs/2004.01227
<p>This letter reports a novel method for supervised machine learning based on
the mathematical formalism that supports quantum mechanics. The method uses
projective quantum measurement as a way of building a prediction function.
Specifically, the correlation between input and output variables is represented
as the state of a bipartite quantum system.<p><a href="http://arxiv.org/abs/2004.01227">read more</a></p>
Mon, 06 Apr 2020 12:54:12 +0200arXiv.org: Quantum Physics: Simulating the effect of weak measurements by a phase damping channel and extraction of bipartite correlations in nuclear magnetic resonance. (arXiv:2004.01237v1 [quant-ph])
http://arxiv.org/abs/2004.01237
<p>Quantum discord is a measure based on local projective measurements which
captures quantum correlations that go beyond entanglement. A change in the
measurement process, achieved by replacing rank-one projectors with a weak
positive operator-valued measure (POVM), allows one to define a quantity termed
as weak quantum discord. In this work, we experimentally simulate the effect of
a weak POVM on a nuclear magnetic resonance quantum information processor.<p><a href="http://arxiv.org/abs/2004.01237">read more</a></p>
Mon, 06 Apr 2020 12:54:12 +0200arXiv.org: Quantum Physics: Algebraic treatment of the Bateman Hamiltonian. (arXiv:2004.01272v1 [quant-ph])
http://arxiv.org/abs/2004.01272
<p>We apply the algebraic method to the Bateman Hamiltonian and obtain its
natural frequencies and ladder operators from the adjoint or regular matrix
representation of that operator. Present analysis shows that the eigenfunctions
compatible with the complex eigenvalues obtained earlier by other authors are
not square integrable. In addition to this, the ladder operators annihilate an
infinite number of such eigenfunctions.
</p>Mon, 06 Apr 2020 12:54:12 +0200arXiv.org: Quantum Physics: Simulation of XXZ Spin Models using Sideband Transitions in Trapped Bosonic Gases. (arXiv:2004.01282v1 [cond-mat.quant-gas])
http://arxiv.org/abs/2004.01282
<p>We theoretically propose and experimentally demonstrate the use of motional
sidebands in a trapped ensemble of $^{87}$Rb atoms to engineer tunable
long-range XXZ spin models. We benchmark our simulator by probing a
ferromagnetic to paramagnetic dynamical phase transition in the so called
Lipkin-Meshkov-Glick (LMG) model, a collective XXZ model plus additional
transverse and longitudinal fields, via Rabi spectroscopy. We experimentally
reconstruct the boundary between the dynamical phases, which is in good
agreement with mean-field theoretical predictions.<p><a href="http://arxiv.org/abs/2004.01282">read more</a></p>
Mon, 06 Apr 2020 12:54:12 +0200