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Generic Bound Coherence under Strictly Incoherent Operations

Author(s): Ludovico Lami, Bartosz Regula, and Gerardo Adesso
We compute analytically the maximal rates of distillation of quantum coherence under strictly incoherent operations (SIO) and physically incoherent operations (PIO), showing that they coincide for all states, and providing a complete description of the phenomenon of bound coherence. In particular, w...
[Phys. Rev. Lett. 122, 150402] Published Fri Apr 19, 2019

Fri, 19/04/2019 - 12:00

Spontaneous generation of phononic entanglement in quantum dark-soliton qubits

Author(s): Muzzamal I. Shaukat, Eduardo V. Castro, and Hugo Terças
We show that entanglement between two solitary qubits in quasi-one-dimensional Bose-Einstein condensates can be spontaneously generated due to quantum fluctuations. Recently we have shown that dark solitons are an appealing platform for qubits thanks to their appreciable long lifetime. We investigat...
[Phys. Rev. A 99, 042326] Published Thu Apr 18, 2019

Thu, 18/04/2019 - 12:00

Learning robust and high-precision quantum controls

Author(s): Re-Bing Wu, Haijin Ding, Daoyi Dong, and Xiaoting Wang
Robust and high-precision quantum control is extremely important but challenging for the functionalization of scalable quantum computation. In this paper, we show that this hard problem can be translated to a supervised machine learning task by thinking of the time-ordered quantum evolution as a lay...
[Phys. Rev. A 99, 042327] Published Thu Apr 18, 2019

Thu, 18/04/2019 - 12:00

Optimal Probabilistic Work Extraction beyond the Free Energy Difference with a Single-Electron Device

Author(s): Olivier Maillet, Paolo A. Erdman, Vasco Cavina, Bibek Bhandari, Elsa T. Mannila, Joonas T. Peltonen, Andrea Mari, Fabio Taddei, Christopher Jarzynski, Vittorio Giovannetti, and Jukka P. Pekola
In very small systems like a single electron transistor, sometimes thermal fluctuations allow single shot extraction of work from the system beyond the bounds of the second law of thermodynamics.
[Phys. Rev. Lett. 122, 150604] Published Thu Apr 18, 2019

Thu, 18/04/2019 - 12:00

Collectively induced exceptional points of quantum emitters coupled to nanoparticle surface plasmons. (arXiv:1904.08133v1 [cond-mat.mes-hall])

Exceptional points, resulting from non-Hermitian degeneracies, have the
potential to enhance the capabilities of quantum sensing. Thus, finding
exceptional points in different quantum systems is vital for developing such
future sensing devices. Taking advantage of the enhanced light-matter
interactions in a confined volume on a metal nanoparticle surface, here we
theoretically demonstrate the existence of exceptional points in a system
consisting of quantum emitters coupled to a metal nanoparticle of subwavelength

Thu, 18/04/2019 - 02:46

Rapid filling of the spin gap with temperature in the Schwinger-boson mean-field theory of the antiferromagnetic Heisenberg kagome model. (arXiv:1807.07071v2 [cond-mat.str-el] UPDATED)

Using Schwinger-boson mean-field theory, we calculate the dynamic spin
structure factor at low temperatures $0<T\ll J$ for the spin-$1/2$
antiferromagnetic Heisenberg kagome model, within the gapped $\mathbb{Z}_2$
spin liquid phase Ansatz. We find that the spectral gap rapidly fills with
temperature, with robust low-energy spectral weight developing by a temperature
of $\Delta/3$, where the spin gap is $2\Delta$ (i.e., $\Delta$ is the spinon
gap), before any appreciable rise in spinon density or change in

Thu, 18/04/2019 - 02:46

Lorentz-invariant, retrocausal, and deterministic hidden variables. (arXiv:1904.08134v1 [quant-ph])

We review several no-go theorems attributed to Gisin and Hardy, Conway and
Kochen purporting the impossibility of Lorentz-invariant deterministic
hidden-variable model for explaining quantum nonlocality. Those theorems claim
that the only known solution to escape the conclusions is either to accept a
preferred reference frame or to abandon the hidden-variable program altogether.
Here we present a different alternative based on a foliation dependent
framework adapted to deterministic hidden variables. We analyse the impact of

Thu, 18/04/2019 - 02:46

Gravitational mass of composite systems. (arXiv:1808.05831v2 [gr-qc] UPDATED)

The equivalence principle in combination with the special relativistic
equivalence between mass and energy, $E=mc^2$, is one of the cornerstones of
general relativity. However, for composite systems a long-standing result in
general relativity asserts that the passive gravitational mass is not simply
equal to the total energy. This seeming anomaly is supported by all explicit
derivations of the dynamics of bound systems, and is only avoided after
time-averaging. Here we rectify this misconception and derive from first

Thu, 18/04/2019 - 02:46

Observation of PT-symmetric quantum interference. (arXiv:1904.08135v1 [quant-ph])

Parity-Time (PT) symmetric quantum mechanics is a complex extension of
conventional Hermitian quantum mechanics in which physical observables possess
a real eigenvalue spectrum. However, an experimental demonstration of the true
quantum nature of PT symmetry has been elusive thus far, as only
single-particle physics has been exploited to date. In our work, we demonstrate
two-particle quantum interference in a PT-symmetric system. We employ
integrated photonic waveguides to reveal that PT-symmetric bunching of

Thu, 18/04/2019 - 02:46

Unifying fast scrambling, thermalization and entanglement through the measurement of FOTOCs in the Dicke model. (arXiv:1808.07134v3 [quant-ph] UPDATED)

Scrambling of quantum information is the process by which information
initially stored in the local degrees of freedom of a quantum many-body system
spreads over its many-body degrees of freedom, becoming inaccessible to local
probes and thus apparently lost. Scrambling and entanglement are key concepts
reconciling seemingly unrelated behaviors including thermalization of isolated
quantum systems and information loss in black holes, and have revolutionized

Thu, 18/04/2019 - 02:46