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Author(s): Raphael Fortes and Gustavo Rigolin
We study the probabilistic (conditional) teleportation protocol when the entanglement needed for its implementation is given by thermal entanglement, i.e., when the entangled resource connecting Alice and Bob is an entangled mixed state described by the canonical ensemble density matrix. Specificall...
[Phys. Rev. A 96, 022315] Published Wed Aug 16, 2017

We show that wireless quantum broadcasting through relativistic quantum
fields is impacted by geometry in nontrivial ways that can be traced to the
no-cloning principle. To study these phenomena, we extend the framework of
models usually employed in the field of relativistic quantum information to
allow for the non-perturbative description of, e.g., quantum state transfer. We
consider, in particular, the case of 1+1 spacetime dimensions, which already
allows a number of interesting scenarios, pointing to, for example, new

The exploitation and characterization of memory effects arising from the
interaction between system and environment is a key prerequisite for quantum
reservoir engineering beyond the standard Markovian limit. In this paper we
investigate a prototype of non-Markovian dynamics experimentally implementable
with superconducting qubits. We rigorously quantify non-Markovianity
highlighting the effects of the environmental temperature on the Markovian to
non-Markovian crossover. We investigate how memory effects influence, and

Operator-sum representations of quantum channels can be obtained by applying
the channel to one subsystem of a maximally entangled state and deploying the
channel-state isomorphism. However, for continuous-variable systems, such
schemes contain natural divergences since the maximally entangled state is
ill-defined. We introduce a method that avoids such divergences by utilizing
finitely entangled (squeezed) states and then taking the limit of arbitrary

On demand single photon emitters (SPEs) play a key role across a broad range
of quantum technologies, including quantum computation, quantum simulation,
quantum metrology and quantum communications. In quantum networks and quantum
key distribution protocols, where photons are employed as flying qubits,
telecom wavelength operation is preferred due to the reduced fibre loss.
However, despite the tremendous efforts to develop various triggered SPE
platforms, a robust source of triggered SPEs operating at room temperature and

We present a fabrication process for fully superconducting interconnects
compatible with superconducting qubit technology. These interconnects allow for
the 3D integration of quantum circuits without introducing lossy amorphous
dielectrics. They are composed of indium bumps several microns tall separated
from an aluminum base layer by titanium nitride which serves as a diffusion
barrier. We measure the whole structure to be superconducting (transition
temperature of 1.1$\,$K), limited by the aluminum. These interconnects have an

We investigate that no-knowledge measurement-based feedback control is
utilized to obtain the estimation precision of the detection efficiency. For
the feedback operators that concern us, no-knowledge measurement is the optimal
way to estimate the detection efficiency. We show that the higher precision can
be achieved for the lower or larger detection efficiency. It is found that
no-knowledge feedback can be used to cancel decoherence. No-knowledge feedback

It is hypothesized that the Langevin time of stochastic quantum quantization
is a physical time over which quantum fields at all values of space and
coordinate time fluctuate. The average over paths becomes a time average as
opposed to an ensemble average. It is further hypothesized that the Langevin
time also paces the motion of particles through coordinate time and is equal to
the coordinate time of the present hypersurface in the frame of the Hubble
expansion. Despite having a preferred frame, special relativity continues to

Scalable quantum photonic systems require efficient single photon sources
coupled to integrated photonic devices. Solid-state quantum emitters can
generate single photons with high efficiency, while silicon photonic circuits
can manipulate them in an integrated device structure. Combining these two
material platforms could, therefore, significantly increase the complexity of
integrated quantum photonic devices. Here, we demonstrate hybrid integration of
solid-state quantum emitters to a silicon photonic device. We develop a

What does it mean for one quantum process to be more disordered than another?
Here we provide a precise answer to this question in terms of a
quantum-mechanical generalization of majorization. The framework admits a
complete description in terms of single-shot entropies, and provides a range of
significant applications. These include applications to the comparison of
quantum statistical models and quantum channels, to the resource theory of
asymmetry, and to quantum thermodynamics. In particular, within quantum