scholarly journals Manifestation of the spontaneous parity-time symmetry breaking phase transition in hot-electron photodetection based on a tri-layered metamaterial

Nanophotonics ◽  
2019 ◽  
Vol 8 (3) ◽  
pp. 495-504 ◽  
Author(s):  
Qiang Bai
Keyword(s):  
Phase Transition ◽  
Theoretical Model ◽  
Symmetry Breaking ◽  
Pt Symmetry ◽  
Coupled Mode Theory ◽  
Hot Electron ◽  
Electron Device ◽  
Coupled Mode ◽  
Time Symmetry ◽  
Existence Conditions

AbstractWe theoretically and numerically demonstrate that the spontaneous parity-time (PT) symmetry breaking phase transition can be realized respectively by using two independent tuning ways in a tri-layered metamaterial that consists of periodic array of metal-semiconductor Schottky junctions. The existence conditions of PT symmetry and its phase transition are obtained by using a theoretical model based on the coupled mode theory. A hot-electron photodetection based on the same tri-layered metamaterial is proposed, which can directly show the spontaneous PT symmetry breaking phase transition in photocurrent and possesses dynamical tunability and switchability. This work extends the concept of PT symmetry into the hot-electron photodetection, enriches the functionality of the metamaterial and the hot-electron device, and has varieties of potential and important applications in optoelectronics, photodetection, photovoltaics, and photocatalytics.

scholarly journals Quantum Zeno effects across a parity-time symmetry breaking transition in atomic momentum space

2021 ◽  
Vol 7 (1) ◽  
Author(s):  
Tao Chen ◽  
Wei Gou ◽  
Dizhou Xie ◽  
Teng Xiao ◽  
Wei Yi ◽  
...  
Keyword(s):  
Symmetry Breaking ◽  
State Of The Art ◽  
Cold Atom ◽  
Pt Symmetry ◽  
Level System ◽  
Flexible Control ◽  
Time Symmetry ◽  
Symmetry Phase ◽  
Lattice Quantum ◽  
Atomic Momentum

AbstractWe experimentally study quantum Zeno effects in a parity-time (PT) symmetric cold atom gas periodically coupled to a reservoir. Based on the state-of-the-art control of inter-site couplings of atoms in a momentum lattice, we implement a synthetic two-level system with passive PT symmetry over two lattice sites, where an effective dissipation is introduced through repeated couplings to the rest of the lattice. Quantum Zeno (anti-Zeno) effects manifest in our experiment as the overall dissipation of the two-level system becoming suppressed (enhanced) with increasing coupling intensity or frequency. We demonstrate that quantum Zeno regimes exist in the broken PT symmetry phase, and are bounded by exceptional points separating the PT symmetric and PT broken phases, as well as by a discrete set of critical coupling frequencies. Our experiment establishes the connection between PT-symmetry-breaking transitions and quantum Zeno effects, and is extendable to higher dimensions or to interacting regimes, thanks to the flexible control with atoms in a momentum lattice.

scholarly journals Photochemical Methods for the Real-Time Observation of Phase Transition Processes upon Crystallization

Symmetry ◽  
2020 ◽  
Vol 12 (10) ◽  
pp. 1726
Author(s):  
Fuyuki Ito
Keyword(s):  
Phase Transition ◽  
Phase Transformation ◽  
Symmetry Breaking ◽  
Real Time ◽  
Fluorescence Spectra ◽  
Time Symmetry ◽  
Time Observation ◽  
Fluorescent Molecules ◽  
Real Time Observation ◽  
Crystal Phase Transformation

We have used the fluorescence detection of phase transformation dynamics of organic compounds by photochemical methods to observe a real-time symmetry breaking process. The organic fluorescent molecules vary the fluorescence spectra depending on molecular aggregated states, implying fluorescence spectroscopy can be applied to probe the evolution of the molecular-assembling process. As an example, the amorphous-to-crystal phase transformation and crystallization with symmetry breaking at droplet during the solvent evaporation of mechanofluorochromic molecules are represented in this review.

scholarly journals Quantum simulation of parity–time symmetry breaking with a superconducting quantum processor

2021 ◽  
Vol 4 (1) ◽  
Author(s):  
Shruti Dogra ◽  
Artem A. Melnikov ◽  
Gheorghe Sorin Paraoanu
Keyword(s):  
Phase Transition ◽  
Symmetry Breaking ◽  
Critical Exponent ◽  
Quantum Effects ◽  
Quantum Simulation ◽  
Quantum Regime ◽  
Exceptional Points ◽  
Time Symmetry ◽  
Quantum Processor

Abstract The observation of genuine quantum effects in systems governed by non-Hermitian Hamiltonians has been an outstanding challenge in the field. Here we simulate the evolution under such Hamiltonians in the quantum regime on a superconducting quantum processor by using a dilation procedure involving an ancillary qubit. We observe the parity–time ($${\mathcal{PT}}$$ PT )-symmetry breaking phase transition at the exceptional points, obtain the critical exponent, and show that this transition is associated with a loss of state distinguishability. In a two-qubit setting, we show that the entanglement can be modified by local operations.

scholarly journals Phase-coupled simultaneous coherent perfect absorption and controllable hot-electron photodetection in Schottky junction metamaterial

Nanophotonics ◽  
2020 ◽  
Vol 9 (1) ◽  
pp. 211-224
Author(s):  
Qiang Bai
Keyword(s):  
Near Field ◽  
Schottky Junction ◽  
Coupled Mode Theory ◽  
Hot Electron ◽  
Phase Coupling ◽  
Perfect Absorption ◽  
Field Coupling ◽  
Coupled Mode ◽  
Coherent Perfect Absorption ◽  
New Type

AbstractWe report a new type of coherent perfect absorption that is determined by the phase coupling between metaatoms and is referred to as the phase-coupled simultaneous coherent perfect absorption (PC-SCPA) for antisymmetric and symmetric incidences and especially the PC-SCPA for antisymmetric and symmetric incidences can be simultaneously achieved in the same bi-layered Schottky junction metamaterial possessing the phase coupling. Our proposed mechanism exploits the phase coupling between metaatoms, which is in contrast with the existing mechanism which depends on the near-field coupling. The theory of PC-SCPA is provided using coupled mode theory with the phase coupling. The operating wavelengths of PC-SCPA are insensitive to the variations of the spacing distances between metaatoms in the lateral and vertical directions. An infrared PC-SCPA-based hot-electron photodetection with dynamically switchable operating wavelengths and dynamically tunable bandwidth is theoretically and numerically verified in the same bi-layered Schottky junction metamaterial. The peak of spectrum of responsivity for antisymmetric and symmetric incidences can be switched to the same wavelength only by altering the phase coupling. Our study may build the bridge among the new type of PC-SCPA, metamaterial, and hot electron and may find potential and significant applications in hot-electron photodetection.

Coupled Mode Theory Under The Parity-Time Symmetry Frame

2013 ◽  
Vol 31 (15) ◽  
pp. 2477-2481 ◽  
Author(s):  
Yubo Li ◽  
Xianxin Guo ◽  
Li Chen ◽  
Chao Xu ◽  
Jianyi Yang ◽  
...  
Keyword(s):  
Coupled Mode Theory ◽  
Mode Theory ◽  
Coupled Mode ◽  
Time Symmetry

scholarly journals Biosensing Near the Exceptional Point Based on Resonant Optical Tunneling Effect

Micromachines ◽  
2021 ◽  
Vol 12 (4) ◽  
pp. 426
Author(s):  
Yang Liu ◽  
Pengyun Yan ◽  
Feng Liu ◽  
Aoqun Jian ◽  
Shengbo Sang
Keyword(s):  
Exceptional Point ◽  
Tunneling Effect ◽  
Coupled Mode Theory ◽  
Environment Protection ◽  
Label Free ◽  
Liquid Sample ◽  
Water Safety ◽  
Coupled Mode ◽  
Drinking Water Safety ◽  
Optical Tunneling

Inspired by exceptional point (EP) sensing in non-Hermitian systems, in this work, a label-free biosensor for detecting low-concentration analytes is proposed, via a special multilayer structure: a resonant optical tunneling resonator. Due to the square root topology near the exceptional point, a recognized target analyte perturbs the system deviated from the exceptional point, leading to resolvable modes splitting in the transmission spectrum. The performance of the designed sensor is analyzed by the coupled-mode theory and transfer matrix method, separately. Here, the simulation results demonstrate that the obtained sensitivity is 17,120 nm/imaginary part unit of refractive index (IP) and the theoretical detection limit is 4.2 × 10−8 IP (regarding carcinoembryonic antigen (CEA), the minimum detection value is 1.78 ng). Instead of the typical diffusion manner, the liquid sample is loaded by convection, which can considerably improve the efficiency of sample capture and shorten the response time of the sensor. The sketched sensor may find potential application in the fields of biomedical detection, environment protection, and drinking water safety.

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