158 research outputs found
An exact solution of spherical mean-field plus orbit-dependent non-separable pairing model with two non-degenerate j-orbits
An exact solution of nuclear spherical mean-field plus orbit-dependent
non-separable pairing model with two non-degenerate j-orbits is presented. The
extended one-variable Heine-Stieltjes polynomials associated to the Bethe
ansatz equations of the solution are determined, of which the sets of the zeros
give the solution of the model, and can be determined relatively easily. A
comparison of the solution to that of the standard pairing interaction with
constant interaction strength among pairs in any orbit is made. It is shown
that the overlaps of eigenstates of the model with those of the standard
pairing model are always large, especially for the ground and the first excited
state. However, the quantum phase crossover in the non-separable pairing model
cannot be accounted for by the standard pairing interaction.Comment: 5 pages, 1 figure, LaTe
Topological superconductivity with large Chern numbers in a ferromagnetic metal-superconductor heterostructure
The ferromagnetic metal-superconductor heterostructure with interface Rashba
spin-orbit hopping is a promising candidate for topological superconductivity.
We study the interplay between the interface Rashba hopping and the intrinsic
Dresselhaus spin-orbit coupling in this heterostructure, and demonstrate rich
topological phases with five distinct Chern numbers. In particular, we find a
topological state with a Chern number as large as four in the parameter space
of the heterostructure. We calculate the Berry curvatures that construct the
Chern numbers, and show that these Berry curvatures induce anomalous thermal
Hall transport of the superconducting quasiparticles. We reveal chiral edge
states in the topological phases, as well as helical edge states in the trivial
phase, and show that the wave functions of these edge states mostly concentrate
on the ferrometal layer of the heterostructure
Reconfigurable phase contrast microscopy with correlated photon pairs
A phase-sensitive microscopy technique is proposed and demonstrated that
employs the momentum correlations inherent in spontaneous parametric
down-conversion. One photon from a correlated pair is focused onto a
microscopic target while the other is measured in the Fourier plane. This
provides knowledge of the position and angle of illumination for every photon
striking the target, allowing full post-production control of the illumination
angle used to form an image. The versatility of this approach is showcased with
asymmetric illumination and differential phase contrast imaging, without any
beam blocks or moving parts.Comment: 5 pages, 3 figure
Characterisation of a single photon event camera for quantum imaging
We show a simple yet effective method that can be used to characterize the
per pixel quantum efficiency and temporal resolution of a single photon event
camera for quantum imaging applications. Utilizing photon pairs generated
through spontaneous parametric down-conversion, the detection efficiency of
each pixel, and the temporal resolution of the system, are extracted through
coincidence measurements. We use this method to evaluate the TPX3CAM, with
appended image intensifier, and measure an average efficiency of 7.4% and a
temporal resolution of 7.3ns. Furthermore, this technique reveals important
error mechanisms that can occur in post-processing. We expect that this
technique, and elements therein, will be useful to characterise other quantum
imaging systems.Comment: 9 pages, 5 figure
Simultaneous entanglement swapping of multiple orbital angular momentum states of light
Entanglement swapping generates remote quantum correlations between particles
that have not interacted and is the cornerstone of long-distance quantum
communication, quantum networks, and fundamental tests of quantum science. In
the context of spatial modes of light, high-dimensional entanglement provides
an avenue to increase the bandwidth of quantum communications and provides more
stringent limits for tests of quantum foundations. Here we simultaneously swap
the entanglement of multiple orbital angular momentum states of light. The
system is based on a degenerate filter that cannot distinguish between
different anti-symmetric states, and thus entanglement swapping occurs for
several thousand pairs of spatial light modes simultaneously
Experimental realisations of the fractional Schr\"{o}dinger equation in the temporal domain
The fractional Schr\"{o}dinger equation (FSE) -- a natural extension of the
standard Schr\"{o}dinger equation -- is the basis of fractional quantum
mechanics. It can be obtained by replacing the kinetic-energy operator with a
fractional derivative. Here, we report the experimental realisation of an
optical FSE for femtosecond laser pulses in the temporal domain. Programmable
holograms and the single-shot measurement technique are respectively used to
emulate a \textit{L\'evy waveguide} and to reconstruct the amplitude and phase
of the pulses. Varying the L\'evy index of the FSE and the initial pulse, the
temporal dynamics is observed in diverse forms, including solitary, splitting
and merging pulses, double Airy modes, and ``rain-like'' multi-pulse patterns.
Furthermore, the transmission of input pulses carrying a fractional phase
exhibits a ``fractional-phase protection'' effect through a regular
(non-fractional) material. The experimentally generated fractional time-domain
pulses offer the potential for designing optical signal-processing schemes.Comment: This manuscript reports on experimental progress in fractional
Schrodinger equations. Welcome to your comments and suggestions
Experimental Investigation on R245fa Throttling Devices under High Temperature
The experiments on mass flow rate characteristics of R245fa refrigerant flowing through throttling devices including seven capillary tubes and the electronic expansion valve were carried out under the high-temperature working conditions. By combining data analysis with flow correlations, the design basis that is applicable to R245fa throttling devices can be obtained. By comparing the experimental mass flow rate with that predicted by Jung Correlation and Kim Correlation, it can be concluded that root mean square deviations of two correlations are 3.2 % and 3.3%, respectively. The root mean square deviation for electronic expansion valve is 4.5%. The conclusions offer high-accuracy design basis for throttling devices selection of high-temperature heat pump systems using R245fa as refrigerant
Quantum correlation light-field microscope with extreme depth of field
Light-field microscopy (LFM) is a 3D microscopy technique whereby volumetric
information of a sample is gained in a single shot by simultaneously capturing
both position and angular information of light emanating from a sample.
Conventional LFM designs require a trade-off between position and angular
resolution, requiring one to sacrifice resolving power for increased depth of
field (DOF) or vice versa. In this work, we demonstrate a LFM design that does
not require this trade-off by utilizing the inherent strong correlation between
spatial-temporal entangled photon pairs. Here, one photon from the pair is used
to illuminate a sample from which the position information of the photon is
captured directly by a camera. By virtue of the strong momentum/angular
anti-correlation between the two photons, the angular information of the
illumination photon can then be inferred by measuring the angle of its
entangled partner on a different camera. We demonstrate that a resolving power
of 5m can be maintained with a DOF of m, over an order of
magnitude larger compared to conventional LFM designs. In the extreme, at a
resolving power of 100m, it is possible to achieve near infinite DOFComment: 14 pages, 9 figure
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