1,353 research outputs found
Generation of long-living entanglement between two separate atoms
A scheme for non-conditional generation of long-living maximally entangled
states between two spatially well separated atoms is proposed. In the scheme,
-type atoms pass a resonator-like equipment of dispersing and
absorbing macroscopic bodies giving rise to body-assisted electromagnetic field
resonances of well-defined heights and widths. Strong atom-field coupling is
combined with weak atom-field coupling to realize entanglement transfer from
the dipole-allowed transitions to the dipole-forbidden transitions, thereby the
entanglement being preserved when the atoms depart from the bodies and from
each other. The theory is applied to the case of the atoms passing by a
microsphere.Comment: 13 pages, 5 figure
Proximity for Sums of Composite Functions
We propose an algorithm for computing the proximity operator of a sum of
composite convex functions in Hilbert spaces and investigate its asymptotic
behavior. Applications to best approximation and image recovery are described
From first-order magneto-elastic to magneto-structural transition in (Mn,Fe)1.95P0.50Si0.50 compounds
We report on structural, magnetic and magnetocaloric properties of
MnxFe1.95-xP0.50Si0.50 (x > 1.10) compounds. With increasing the Mn:Fe ratio, a
first-order magneto-elastic transition gradually changes into a first-order
magneto-structural transition via a second-order magnetic transition. The study
also shows that thermal hysteresis can be tuned by varying the Mn:Fe ratio.
Small thermal hysteresis (less than 1 K) can be obtained while maintaining a
giant magnetocaloric effect. This achievement paves the way for real
refrigeration applications using magnetic refrigerants.Comment: 4 pages, 3 figures, Supplemental Materia
Interaction effects and charge quantization in single-particle quantum dot emitters
We discuss a theoretical model of an on-demand single-particle emitter that
employs a quantum dot, attached to an integer or fractional quantum Hall edge
state. Via an exact mapping of the model onto the spin-boson problem we show
that Coulomb interactions between the dot and the chiral quantum Hall edge
state, unavoidable in this setting, lead to a destruction of precise charge
quantization in the emitted wave-packet. Our findings cast doubts on the
viability of this set-up as a single-particle source of quantized charge
pulses. We further show how to use a spin-boson master equation approach to
explicitly calculate the current pulse shape in this set-up.Comment: 5+5 pages, 3 figures, fixed typos, update Supplement Material and
update figure
Efficiency of tunable band-gap structures for single-photon emission
The efficiency of recently proposed single-photon emitting sources based on
tunable planar band-gap structures is examined. The analysis is based on the
study of the total and ``radiative'' decay rates, the expectation value of
emitted radiation energy and its collimating cone. It is shown that the scheme
operating in the frequency range near the defect resonance of a defect band-gap
structure is more efficient than the one operating near the band edge of a
perfect band-gap structure.Comment: 9 pages, 7 figure
On the Dichotomy between the Nodal and Antinodal Excitations in High-temperature Superconductors
Angle-resolved photoemission data on optimally- and under-doped high
temperature superconductors reveal a dichotomy between the nodal and antinodal
electronic excitations. In this paper we propose an explanation of this unusual
phenomenon by employing the coupling between the quasiparticle and the
commensurate/incommensurate magnetic excitations.Comment: 11 pages, 9 figure
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