arXiv subjects

Yan Xue

Publications and source records attributed to Yan Xue.

5 recordsLinked to original sources

arXiv2021

Controllable Bistability and Squeezing of Confined Polariton Dark Solitons

The generation of squeezed light in semiconductor materials opens opportunities for building on-chip devices that are operated at the quantum level. Here we study theoretically a squeezed light source of polariton dark solitons confined in a geometric potential well of semiconductor microcavities in the strong coupling regime. We show that polariton dark solitons of odd and even parities can be created by tuning the potential depth. When driving the potential depth linearly, a bistability of solitons with the two different parities can be induced. Strong intensity squeezing is obtained near the turning point of the bistability due to the large nonlinear interaction, which can be controlled by Feshbach resonance. The phase diagram of the bistability and squeezing of the dark solitons is obtained through large scale numerical calculations. Our study contributes to the current efforts in realizing topological excitations and squeezed light sources with solid-state devices.

physics.optics↗

arXiv2021

A topological attractor of vortices as a clock generator based on polariton superfluids

We reveal a topologically protected persistent oscillatory dynamics of a polariton superfluid, which is driven non-resonantly by a super-Gaussian laser beam in a planar semiconductor microcavity subjected to an external C-shape potential. We find persistent oscillations, characterized by a topological attractor, that are based on the dynamical behavior of small Josephson vortices rotating around the outside edge of the central vortex. The attractor is being formed due to the inverse energy cascade accompanied by the growth of the incompressible kinetic energy. The attractor displays a remarkable stability towards perturbations and it may be tuned by the pump laser intensity to two distinct frequency ranges: 20.16$\pm$0.14 GHz and 48.4$\pm$1.2 GHz. This attractor is bistable due to the chirality of the vortex. The switching between two stable states is achieved by altering the pump power or by adding an extra incoherent Gaussian pump beam.

cond-mat.mes-hall↗

arXiv2020

Split-ring polariton condensates as macroscopic two-level quantum systems

Superposition states of circular currents of exciton-polaritons mimic the superconducting flux qubits. The phase of a polariton fluid must change by an integer number of $2π$, when going around the ring. If one introduces a $π$-phase delay line in the ring, the fluid is obliged to propagate a clockwise or anticlockwise circular current to reduce the total phase gained over one round-trip to zero or to build it up to $2π$. We show that such a $π$-delay line can be provided by a dark soliton pinned to a potential well created by a C-shape non-resonant pump-spot. The resulting split-ring polariton condensates exhibit pronounced coherent oscillations passing periodically through clockwise and anticlockwise current states. These oscillations may persist far beyond the coherence time of polariton condensates. The qubits based on split-ring polariton condensates are expected to possess very high figures of merit that makes them a valuable alternative to superconducting qubits. The use of the dipole-polarized polaritons allows to control coherently the state of the qubit with the external electric field. This is shown to be one of the tools for realization of single-qubit logic operations. We propose the design of an $i$SWAP gate based on a pair of coupled polariton qubits. To demonstrate the capacity of the polariton platform for quantum computations, we propose a protocol for the realization of the Deutsch's algorithm with polariton qubit networks.

cond-mat.mes-hall↗

arXiv2019

Gastroscopic Panoramic View: Application to Automatic Polyps Detection under Gastroscopy

Endoscopic diagnosis is an important means for gastric polyp detection. In this paper, a panoramic image of gastroscopy is developed, which can display the inner surface of the stomach intuitively and comprehensively. Moreover, the proposed automatic detection solution can help doctors locate the polyps automatically, and reduce missed diagnosis. The main contributions of this paper are: firstly, a gastroscopic panorama reconstruction method is developed. The reconstruction does not require additional hardware devices, and can solve the problem of texture dislocation and illumination imbalance properly; secondly, an end-to-end multi-object detection for gastroscopic panorama is trained based on deep learning framework. Compared with traditional solutions, the automatic polyp detection system can locate all polyps in the inner wall of stomach in real time and assist doctors to find the lesions. Thirdly, the system was evaluated in the Affiliated Hospital of Zhejiang University. The results show that the average error of the panorama is less than 2 mm, the accuracy of the polyp detection is 95%, and the recall rate is 99%. In addition, the research roadmap of this paper has guiding significance for endoscopy-assisted detection of other human soft cavities.

eess.IV↗

arXiv2014

Creation and abrupt decay of a quasi-stationary dark soliton in a polariton condensate

We predict the existence of a self-localized solution in a nonresonantly pumped exciton-polariton condensate. The solution has a shape resembling the well-known hyperbolic tangent profile of the dark soliton, but exhibits several distinct features. We find that it performs small oscillations, which are transformed into 'soliton explosions' at lower pumping intensities. Moreover, after hundreds or thousands of picoseconds of apparently stable evolution the soliton decays abruptly, which is explained by the acceleration instability found previously in the Bekki-Nozaki hole solutions of the complex Ginzburg-Landau equation. We show that the soliton can be formed spontaneously from a small seed in the polariton field or by using spatial modulation of the pumping profile.

nlin.PS↗