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QUROPE - aggregated feeds in category PhysicsenarXiv.org: Quantum Physics: Open problem in orthogonal polynomials. (arXiv:1709.06081v1 [math-ph])
http://arxiv.org/abs/1709.06081
<p>Using an algebraic method for solving the wave equation in quantum mechanics,
we encountered two new classes of orthogonal polynomials on the real line. Up
to now, these polynomials are defined by their three-term recursion relations
and initial values. However, their other properties like the weight functions,
generating functions, orthogonality, Rodrigues-type formulas, etc. are yet to
be derived analytically.<p><a href="http://arxiv.org/abs/1709.06081">read more</a></p>
Wed, 20 Sep 2017 20:37:45 +0200arXiv.org: Quantum Physics: Effect of magnetization on the tunneling anomaly in compressible quantum Hall states. (arXiv:1709.06091v1 [cond-mat.str-el])
http://arxiv.org/abs/1709.06091
<p>Tunneling of electrons into a two-dimensional electron system is known to
exhibit an anomaly at low bias, in which the tunneling conductance vanishes due
to a many-body interaction effect. Recent experiments have measured this
anomaly between two copies of the half-filled Landau level as a function of
in-plane magnetic field, and they suggest that increasing spin polarization
drives a deeper suppression of tunneling.<p><a href="http://arxiv.org/abs/1709.06091">read more</a></p>
Wed, 20 Sep 2017 20:37:45 +0200arXiv.org: Quantum Physics: Universally Fisher-symmetric informationally complete measurements. (arXiv:1709.06112v1 [quant-ph])
http://arxiv.org/abs/1709.06112
<p>A quantum measurement is Fisher symmetric if it provides uniform and maximal
information on all parameters that characterize the quantum state of interest.
Using (complex projective) 2-designs, we construct measurements on a pair of
identically prepared quantum states that are Fisher-symmetric for all pure
states. Such measurements are optimal in achieving the minimal statistical
error without adaptive measurements. We then determine all collective
measurements on a pair that are Fisher-symmetric for the completely mixed state
and for all pure states simultaneously.<p><a href="http://arxiv.org/abs/1709.06112">read more</a></p>
Wed, 20 Sep 2017 20:37:45 +0200arXiv.org: Quantum Physics: Provably-Secure and High-Rate Quantum Key Distribution with Time-Bin Qudits. (arXiv:1709.06135v1 [quant-ph])
http://arxiv.org/abs/1709.06135
<p>The security of conventional cryptography systems is threatened in the
forthcoming era of quantum computers. Quantum key distribution (QKD) features
fundamentally proven security and offers a promising option for quantum-proof
cryptography solution. Although prototype QKD systems over optical fiber have
been demonstrated over the years, the key generation rates remain several
orders-of-magnitude lower than current classical communication systems.<p><a href="http://arxiv.org/abs/1709.06135">read more</a></p>
Wed, 20 Sep 2017 20:37:45 +0200arXiv.org: Quantum Physics: Entanglement fluctuation theorems. (arXiv:1709.06139v1 [quant-ph])
http://arxiv.org/abs/1709.06139
<p>Pure state entanglement transformations have been thought of as irreversible,
with reversible transformations generally only possible in the limit of many
copies. Here, we show that reversible entanglement transformations do not
require processing on the many copy level, but can instead be undertaken on
individual systems, provided the amount of entanglement which is produced or
consumed is allowed to fluctuate. We derive necessary and sufficient conditions
for entanglement manipulations in this case.<p><a href="http://arxiv.org/abs/1709.06139">read more</a></p>
Wed, 20 Sep 2017 20:37:44 +0200arXiv.org: Quantum Physics: n-cluster models in a transverse magnetic field. (arXiv:1709.06147v1 [quant-ph])
http://arxiv.org/abs/1709.06147
<p>In this paper we analize a family of one dimensional fully analytically
solvable models, named the n-cluster models in a transverse magnetic field, in
which a many-body cluster interaction competes with a uniform transverse
magnetic field. These models, independently by the cluster size n + 2, exibit a
quantum phase transition, that separates a paramagnetic phase from a cluster
one, that corresponds to a nematic ordered phase or a symmetry-protected
topological ordered phase for even or odd n respectively.<p><a href="http://arxiv.org/abs/1709.06147">read more</a></p>
Wed, 20 Sep 2017 20:37:44 +0200arXiv.org: Quantum Physics: Andreev reflections and the quantum physics of black holes. (arXiv:1709.06154v1 [gr-qc])
http://arxiv.org/abs/1709.06154
<p>We establish an analogy between superconductor-metal interfaces and the
quantum physics of a black hole, using the proximity effect. We show that the
metal-superconductor interface can be thought of as an event horizon and
Andreev reflection from the interface is analogous to the Hawking radiation in
black holes. We describe quantum information transfer in Andreev reflection
with a final state projection model similar to the Horowitz-Maldacena model for
black hole evaporation.<p><a href="http://arxiv.org/abs/1709.06154">read more</a></p>
Wed, 20 Sep 2017 20:37:44 +0200arXiv.org: Quantum Physics: Quantum Randomness Generation by Probability Estimation with Classical Side Information. (arXiv:1709.06159v1 [quant-ph])
http://arxiv.org/abs/1709.06159
<p>We develop a framework for certifying randomness from Bell-test trials based
on directly estimating the probability of the measurement outcomes with
adaptive test supermartingales. The number of trials need not be predetermined,
and one can stop performing trials early, as soon as the desired amount of
randomness is extractable. It can be used with arbitrary, partially known and
time-dependent probabilities for the random settings choices.<p><a href="http://arxiv.org/abs/1709.06159">read more</a></p>
Wed, 20 Sep 2017 20:37:44 +0200arXiv.org: Quantum Physics: Observation of local entanglement oscillation in free space. (arXiv:1709.06191v1 [physics.optics])
http://arxiv.org/abs/1709.06191
<p>It is well known that the entanglement of a quantum state is invariant under
local unitary transformations. It dictates, for example, that the degree of
entanglement of a photon pair in a Bell state remains maximally entangled
during propagation in free-space. Here we outline a scenario where this
paradigm does not hold.<p><a href="http://arxiv.org/abs/1709.06191">read more</a></p>
Wed, 20 Sep 2017 20:37:44 +0200arXiv.org: Quantum Physics: Mixed basis quantum key distribution with linear optics. (arXiv:1709.06194v1 [quant-ph])
http://arxiv.org/abs/1709.06194
<p>Two-qubit quantum codes have been suggested to obtain better efficiency and
higher loss tolerance in quantum key distribution. Here, we propose a two-qubit
quantum key distribution protocol based on a mixed basis consisting of two Bell
states and two states from the computational basis. All states can be generated
from a single entangled photon pair resource by using local operations on only
one auxiliary photon. Compared to other schemes it is also possible to
deterministically discriminate all states using linear optics.<p><a href="http://arxiv.org/abs/1709.06194">read more</a></p>
Wed, 20 Sep 2017 20:37:44 +0200