scholarly journals GHZ-like states in the Qubit-Qudit Rabi model

2021 ◽  
Vol 11 (6) ◽  
Author(s):  
Yuan Shen ◽  
Giampiero Marchegiani ◽  
Gianluigi Catelani ◽  
Luigi Amico ◽  
Ai Qun Liu ◽  
...  
Keyword(s):  
Strong Coupling ◽  
Coupled System ◽  
Relevant Information ◽  
Tripartite Entanglement ◽  
Bipartite Entanglement ◽  
Strongly Coupled ◽  
Future Studies ◽  
Adiabatic Switching ◽  
State Transfer ◽  
Rabi Model

We study a Rabi type Hamiltonian system in which a qubit and a dd-level quantum system (qudit) are coupled through a common resonator. In the weak and strong coupling limits the spectrum is analysed through suitable perturbative schemes. The analysis show that the presence of the multilevels of the qudit effectively enhance the qubit-qudit interaction. The ground state of the strongly coupled system is found to be of Greenberger-Horne-Zeilinger (GHZ) type. Therefore, despite the qubit-qudit strong coupling, the nature of the specific tripartite entanglement of the GHZ state suppresses the bipartite entanglement. We analyze the system dynamics under quenching and adiabatic switching of the qubit-resonator and qudit-resonator couplings. In the quench case, we found that the non-adiabatic generation of photons in the resonator is enhanced by the number of levels in the qudit. The adiabatic control represents a possible route for preparation of GHZ states. Our analysis provides relevant information for future studies on coherent state transfer in qubit-qudit systems.

scholarly journals Strong coupling of a plasmonic nanoparticle to a semiconductor nanowire

Nanophotonics ◽  
2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Yingying Jin ◽  
Liu Yang ◽  
Chenxinyu Pan ◽  
Zhangxing Shi ◽  
Bowen Cui ◽  
...  
Keyword(s):  
Strong Coupling ◽  
Coupled System ◽  
Resonance Wavelength ◽  
Transverse Magnetic ◽  
Spectral Shift ◽  
Au Nanoparticle ◽  
Localized Surface Plasmon ◽  
Nanowire Diameter ◽  
Plasmonic Nanoparticle ◽  
Au Nanosphere

Abstract By placing a single Au nanoparticle on the surface of a cadmium sulfide (CdS) nanowire, we demonstrate strong coupling of localized surface plasmon resonance (LSPR) modes in the nanoparticle and whispering gallery modes (WGMs) in the nanowire. For a 50-nm-diameter Au-nanosphere particle, strong coupling occurs when the nanowire diameter is between 300 and 600 nm, with a mode splitting up to 80 meV. Using a temperature-induced spectral shift of the resonance wavelength, we also observe the anticrossing behavior in the strongly coupled system. In addition, since the Au nanosphere has spherical symmetry, the supported LSPR mode can be selectively coupled with transverse electric (TE) and transverse magnetic (TM) WGMs in the nanowire. The ultracompact strong-coupling system shown here may provide a versatile platform for studying hybrid “photon–plasmon” nanolasers, nonlinear optical devices, and nanosensors.

scholarly journals Fundamental limitations of the mode temperature concept in strongly coupled systems

2020 ◽  
Vol 75 (8) ◽  
pp. 803-807
Author(s):  
Svend-Age Biehs ◽  
Achim Kittel ◽  
Philippe Ben-Abdallah
Keyword(s):  
Heat Transfer ◽  
Heat Exchange ◽  
Strong Coupling ◽  
Quantum Systems ◽  
Coupled Systems ◽  
Strong Coupling Limit ◽  
Strongly Coupled ◽  
Fundamental Limitations ◽  
Temperature Concept ◽  
Vacuum Gap

AbstractWe theoretically analyze heat exchange between two quantum systems in interaction with external thermostats. We show that in the strong coupling limit the widely used concept of mode temperatures loses its thermodynamic foundation and therefore cannot be employed to make a valid statement on cooling and heating in such systems; instead, the incorrectly applied concept may result in a severe misinterpretation of the underlying physics. We illustrate these general conclusions by discussing recent experimental results reported on the nanoscale heat transfer through quantum fluctuations between two nanomechanical membranes separated by a vacuum gap.

scholarly journals Generation and dynamics of entangled fermion–photon–phonon states in nanocavities

Nanophotonics ◽  
2020 ◽  
Vol 10 (1) ◽  
pp. 491-511 ◽  
Author(s):  
Mikhail Tokman ◽  
Maria Erukhimova ◽  
Yongrui Wang ◽  
Qianfan Chen ◽  
Alexey Belyanin
Keyword(s):  
Emission Spectra ◽  
Coupled System ◽  
Vibrational Modes ◽  
Tripartite Entanglement ◽  
Quantum Emitter ◽  
Parametric Resonances ◽  
Analytic Expressions ◽  
Entangled Quantum States ◽  
Formation And Evolution ◽  
Quantum Optomechanics

AbstractWe develop the analytic theory describing the formation and evolution of entangled quantum states for a fermionic quantum emitter coupled simultaneously to a quantized electromagnetic field in a nanocavity and quantized phonon or mechanical vibrational modes. The theory is applicable to a broad range of cavity quantum optomechanics problems and emerging research on plasmonic nanocavities coupled to single molecules and other quantum emitters. The optimal conditions for a tripartite entanglement are realized near the parametric resonances in a coupled system. The model includes dissipation and decoherence effects due to coupling of the fermion, photon, and phonon subsystems to their dissipative reservoirs within the stochastic evolution approach, which is derived from the Heisenberg–Langevin formalism. Our theory provides analytic expressions for the time evolution of the quantum state and observables and the emission spectra. The limit of a classical acoustic pumping and the interplay between parametric and standard one-photon resonances are analyzed.

Article

1999 ◽  
Vol 77 (11) ◽  
pp. 1810-1812 ◽  
Author(s):  
Alex D Bain
Keyword(s):  
Spin System ◽  
Coupled System ◽  
Coupled Systems ◽  
Physical Reason ◽  
Strongly Coupled ◽  
System Combination ◽  
First Order ◽  
Weakly Coupled ◽  
Quantum Transitions ◽  
Weakly Coupled Systems

Strongly coupled spin systems provide many curious and interesting effects in NMR spectra, one of which is the presence of unexpected (from a first-order viewpoint) lines. A physical reason is given for the presence of these combination lines. The X part of the spectrum of an ABX spin system is analysed as an example. For an ABX system, it is well known that the AB nuclei give a spectrum consisting of two AB-type spectra, corresponding to the two orientations of the X nucleus. It can also be shown that the X part of the spectrum corresponds to the X nucleus undergoing a transition in the presence of an AB-like spin system. For weakly coupled systems, the four observed lines correspond to the four different orientations of the A and B nuclei. For a strongly coupled system, two additional lines may appear, the combination lines. The resulting six lines correspond to the four spin orientations, plus the two zero-quantum transitions. It is shown that these six lines are such that there is no net excitation of the AB-like spin system associated with the X transitions. There is no AB coherence created directly by a pulse applied to X. AB coherence is created as the system evolves, and this is responsible for many of the curious effects. This is shown to be true for all spin sub-systems, which are weakly coupled to a strongly coupled sub-system.Key words: NMR, strong coupling, second-order spectra, ABX spin system, combination lines, spectral analysis.

scholarly journals Dynamics of Strong Coupling Between Free Charge Carriers in Organometal Halide Perovskites and Aluminum Plasmonic States

2022 ◽  
Vol 9 ◽  
Author(s):  
Yang Luo ◽  
Hai Wang ◽  
Le-Yi Zhao ◽  
Yong-Lai Zhang
Keyword(s):  
Strong Coupling ◽  
Transient Absorption ◽  
Perovskite Solar Cells ◽  
Coupled System ◽  
Free Carrier ◽  
Charge Carriers ◽  
Free Charge ◽  
Free Carriers ◽  
Halide Perovskites ◽  
Poor Absorption

We have investigated a strong coupled system composed of a MAPbIxCl3-x perovskite film and aluminum conical nanopits array. The hybrid states formed by surface plasmons and free carriers, rather than the traditional excitons, is observed in both steady-state reflection measurements and transient absorption spectra. In particular, under near upper band resonant excitation, the bleaching signal from the band edge of uncoupled perovskite was completely separated into two distinctive bleaching signals of the hybrid system, which is clear evidence for the formation of strong coupling states between the free carrier–plasmon state. Besides this, a Rabi splitting up to 260 meV is achieved. The appearance of the lower bands can compensate for the poor absorption of the perovskite in the NIR region. Finally, we found that the lifetime of the free carrier–SP hybrid states is slightly shorter than that of uncoupled perovskite film, which can be caused by the ultrafast damping of the SPs modes. These peculiar features on the strong coupled hybrid states based on free charge carriers can open new perspectives for novel plasmonic perovskite solar cells.

scholarly journals Scale-free vortex cascade emerging from random forcing in a strongly coupled system

2008 ◽  
Vol 10 (9) ◽  
pp. 093018 ◽  
Author(s):  
K Rypdal ◽  
B Kozelov ◽  
S Ratynskaia ◽  
B Klumov ◽  
C Knapek ◽  
...  
Keyword(s):  
Coupled System ◽  
Free Vortex ◽  
Strongly Coupled ◽  
Scale Free ◽  
Random Forcing ◽  
Vortex Cascade

scholarly journals Phases of a strongly coupled four-fermion theory

2018 ◽  
Vol 175 ◽  
pp. 03004 ◽  
Author(s):  
David Schaich ◽  
Simon Catterall
Keyword(s):  
Strong Coupling ◽  
Weak Coupling ◽  
Strongly Coupled ◽  
Coupling Phase ◽  
Long Range Correlations ◽  
Mass Gap ◽  
Narrow Region ◽  
Lattice Field ◽  
Lattice Symmetry ◽  
Lattice Fermion

We present ongoing investigations of a four-dimensional lattice field theory with four massless reduced staggered fermions coupled through an SU(4)-invariant fourfermion interaction. As in previous studies of four-fermion and Higgs–Yukawa models with different lattice fermion discretizations, we observe a strong-coupling phase in which the system develops a mass gap without breaking any lattice symmetry. This symmetric strong-coupling phase is separated from the symmetric weak-coupling phase by a narrow region of four-fermi coupling in which the system exhibits long-range correlations.

A strongly coupled 3D ternary Fe2O3@Ni2P/Ni(PO3)2 hybrid for enhanced electrocatalytic oxygen evolution at ultra-high current densities

2019 ◽  
Vol 7 (3) ◽  
pp. 965-971 ◽  
Author(s):  
Xiaodi Cheng ◽  
Zhiyan Pan ◽  
Chaojun Lei ◽  
Yangjun Jin ◽  
Bin Yang ◽  
...  
Keyword(s):  
Strong Coupling ◽  
Oxygen Evolution ◽  
Synergistic Effects ◽  
High Current ◽  
Strongly Coupled ◽  
Highly Active ◽  
Current Densities

A ternary Fe2O3@Ni2P/Ni(PO3)2 hybrid with strong coupling and synergistic effects was developed for highly active OER at ultra-high current densities.

scholarly journals QCD, with strings attached

2016 ◽  
Vol 25 (10) ◽  
pp. 1630006 ◽  
Author(s):  
Alberto Güijosa
Keyword(s):  
String Theory ◽  
Quantum Chromodynamics ◽  
Large Class ◽  
Strong Coupling ◽  
Field Theories ◽  
Strong Coupling Regime ◽  
Efficient Tool ◽  
Strongly Coupled ◽  
Coupled Field ◽  
Gauge Gravity

In the nearly 20 years that have elapsed since its discovery, the gauge-gravity correspondence has become established as an efficient tool to explore the physics of a large class of strongly-coupled field theories. A brief overview is given here of its formulation and a few of its applications, emphasizing attempts to emulate aspects of the strong-coupling regime of quantum chromodynamics (QCD). To the extent possible, the presentation is self-contained, and does not presuppose knowledge of string theory.

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