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Temporal hopping dynamics in exciton-polariton condensation
Authors:
Elena Rozas,
Wojciech Bukalski,
Yannik Brune,
Adbhut Gupta,
Kirk Baldwin,
Loren N. Pfeiffer,
Hassan Alnatah,
Jonathan Beaumariage,
David W. Snoke,
Paolo Comaron,
Marzena H. Szymanska,
Marc Aßmann
Abstract:
Polariton condensates provide a versatile platform for exploring non-equilibrium phase transitions and collective phenomena in open quantum systems. Near the condensation threshold, these systems are particularly sensitive to fluctuations and instabilities, which can strongly influence the condensate formation. Using optical trapping and homodyne detection, we directly access the photon statistics…
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Polariton condensates provide a versatile platform for exploring non-equilibrium phase transitions and collective phenomena in open quantum systems. Near the condensation threshold, these systems are particularly sensitive to fluctuations and instabilities, which can strongly influence the condensate formation. Using optical trapping and homodyne detection, we directly access the photon statistics and second-order correlation function $g^{(2)}(0)$ of the condensate. We show that polariton condensation near the threshold is not a purely static transition, but instead undergoes a dynamical regime characterized by stochastic hopping between condensed and non-condensed states. These intermittent dynamics are accompanied by a gradual reduction of $g^{(2)}(0)$ towards unity, revealing the progressive build-up of coherence even in the presence of strong temporal fluctuations. Numerical simulations, based on a stochastic Truncated Wigner description of the driven-dissipative polariton field, reproduce these dynamics and capture the essential role of noise and reservoir interactions. This work demonstrates that the observed temporal hopping is an intrinsic feature of polariton condensation, providing a dynamical perspective that goes beyond static descriptions of the condensation phase transition.
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Submitted 28 April, 2026;
originally announced April 2026.
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Targeted Polariton Flow Through Tailored Photonic Defects
Authors:
Elena Rozas,
Yannik Brune,
Ken West,
Kirk W. Baldwin,
Loren N. Pfeiffer,
Jonathan Beaumariage,
Hassan Alnatah,
David W. Snoke,
Marc Aßmann
Abstract:
In non-Hermitian open quantum systems, such as polariton condensates, local tailoring of gains and losses opens up an interesting possibility to realize functional optical elements. Here, we demonstrate that deliberately introducing losses via a photonic defect, realized by reducing the quality factor of a DBR mirror locally within an ultrahigh-quality microcavity, may be utilized to create direct…
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In non-Hermitian open quantum systems, such as polariton condensates, local tailoring of gains and losses opens up an interesting possibility to realize functional optical elements. Here, we demonstrate that deliberately introducing losses via a photonic defect, realized by reducing the quality factor of a DBR mirror locally within an ultrahigh-quality microcavity, may be utilized to create directed polariton currents towards the defect. We discuss the role of polariton-polariton interactions in the process and how to tailor the effective decay time of a polariton condensate via coupling to the defect. Our results highlight the far-reaching potential of non-Hermitian physics in polaritonics.
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Submitted 10 September, 2024;
originally announced September 2024.
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Quantum coherence of a long-lifetime exciton-polariton condensate
Authors:
Yannik Brune,
Elena Rozas,
Ken West,
Kirk Baldwin,
Loren N. Pfeiffer,
Jonathan Beaumariage,
Hassan Alnatah,
David W. Snoke,
Marc Aßmann
Abstract:
In recent years, quantum information science has made significant progress, leading to a multitude of quantum protocols for the most diverse applications. States carrying resources such as quantum coherence are a key component for these protocols. In this study, we optimize the quantum coherence of a nonresonantly excited exciton-polariton condensate of long living polaritons by minimizing the con…
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In recent years, quantum information science has made significant progress, leading to a multitude of quantum protocols for the most diverse applications. States carrying resources such as quantum coherence are a key component for these protocols. In this study, we optimize the quantum coherence of a nonresonantly excited exciton-polariton condensate of long living polaritons by minimizing the condensate's interaction with the surrounding reservoir of excitons and free carriers. By combining experimental phase space data with a displaced thermal state model, we observe how quantum coherence builds up as the system is driven above the condensation threshold. Our findings demonstrate that a spatial separation between the condensate and the reservoir enhances the state's maximum quantum coherence directly beyond the threshold. These insights pave the way for integrating polariton systems into hybrid quantum devices and advancing applications in quantum technologies.
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Submitted 30 June, 2024;
originally announced July 2024.
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Coupling Dynamics and Linear Polarization Phenomena in Codirectional Polariton Waveguide Couplers
Authors:
Elena Rozas,
Alexey Yulin,
Sebastian Klembt,
Sven Höfling,
María Dolores Martín,
Luis Viña
Abstract:
In this work, we explore the potential of spin-based integrated devices using polariton waveguides that form codirectional couplers. For suitable coupler parameters, a transfer of condensates between the arms of the coupler, occurs leading to the observation of Josephson-like oscillations. The ability to tune the periodicity of these oscillations opens the way to the design of polaritonic circuits…
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In this work, we explore the potential of spin-based integrated devices using polariton waveguides that form codirectional couplers. For suitable coupler parameters, a transfer of condensates between the arms of the coupler, occurs leading to the observation of Josephson-like oscillations. The ability to tune the periodicity of these oscillations opens the way to the design of polaritonic circuits in which the directionality of the signal towards the output terminals can be controlled. We also investigate the response of the devices to linearly polarized excitation, delving into the dynamics of linear polarization at the output terminals of long couplers, providing valuable insights into the potential applications of spin-based polariton devices, including polariton switches and logic gates with efficient operation. Our results are supported by numerical simulations based on generalized Gross-Pitaevskii equation describing the dynamics of coherent polaritons in spatially non-uniform system. We show, how the coupling and the controllable spin degree of freedom in polariton couplers opens avenues for innovative optical architectures and functionalities.
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Submitted 1 August, 2024; v1 submitted 19 January, 2024;
originally announced January 2024.
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Continuous-variable quantum optics and resource theory for ultrafast semiconductor spectroscopy
Authors:
Carolin Lüders,
Franziska Barkhausen,
Matthias Pukrop,
Elena Rozas,
Jan Sperling,
Stefan Schumacher,
Marc Aßmann
Abstract:
In this review, we discuss the use of continuous variable spectroscopy techniques for investigating quantum coherence and light-matter interactions in semiconductor systems with ultrafast dynamics. We focus on multichannel homodyne detection as a powerful tool to measure the quantum coherence and the full density matrix of a polariton system. By monitoring the temporal decay of quantum coherence i…
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In this review, we discuss the use of continuous variable spectroscopy techniques for investigating quantum coherence and light-matter interactions in semiconductor systems with ultrafast dynamics. We focus on multichannel homodyne detection as a powerful tool to measure the quantum coherence and the full density matrix of a polariton system. By monitoring the temporal decay of quantum coherence in the polariton condensate, we observe coherence times exceeding the nanosecond scale. Our findings, supported by proof-of-concept experiments and numerical simulations, demonstrate the enhanced resourcefulness of the produced system states for modern quantum protocols. The combination of tailored resource quantifiers and ultrafast spectroscopy techniques presented here paves the way for future applications of quantum information technologies.
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Submitted 2 June, 2023;
originally announced June 2023.
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Polariton-dark exciton interactions in bistable semiconductor microcavities
Authors:
Elena Rozas,
Evgeny Sedov,
Yannik Brune,
Sven Höfling,
Alexey Kavokin,
Marc Aßmann
Abstract:
We take advantage of the polariton bistability in semiconductor microcavities to estimate the interaction strength between lower exciton-polariton and dark exciton states. We combine the quasiresonant excitation of polaritons and the nominally forbidden two-photon excitation (TPE) of dark excitons in a GaAs microcavity. To this end, we use an ultranarrow linewidth cw laser for the TPE process that…
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We take advantage of the polariton bistability in semiconductor microcavities to estimate the interaction strength between lower exciton-polariton and dark exciton states. We combine the quasiresonant excitation of polaritons and the nominally forbidden two-photon excitation (TPE) of dark excitons in a GaAs microcavity. To this end, we use an ultranarrow linewidth cw laser for the TPE process that allows us to determine the energy of dark excitons with high spectral resolution. Our results evidence a sharp drop in the polariton transmission intensity and width of the hysteresis cycle when the TPE process is resonant with the dark exciton energy, highly compromising the bistability of the polariton condensate. This behavior demonstrates the existence of a small symmetry breaking such as that produced by an effective in-plane magnetic field, allowing us to directly excite the dark reservoir. We numerically reproduce the collapse of the hysteresis cycle with the increasing dark exciton population, treating the evolution of a polariton condensate in a one-mode approximation, coupled to the exciton reservoir via polariton-exciton scattering processes.
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Submitted 22 May, 2023;
originally announced May 2023.
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Tracking quantum coherence in polariton condensates with time-resolved tomography
Authors:
Carolin Lüders,
Matthias Pukrop,
Franziska Barkhausen,
Elena Rozas,
Christian Schneider,
Sven Höfling,
Jan Sperling,
Stefan Schumacher,
Marc Aßmann
Abstract:
Long-term quantum coherence constitutes one of the main challenges when engineering quantum devices. However, easily accessible means to quantify complex decoherence mechanisms are not readily available, nor are sufficiently stable systems. We harness novel phase-space methods - expressed through non-Gaussian convolutions of highly singular Glauber-Sudarshan quasiprobabilities - to dynamically mon…
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Long-term quantum coherence constitutes one of the main challenges when engineering quantum devices. However, easily accessible means to quantify complex decoherence mechanisms are not readily available, nor are sufficiently stable systems. We harness novel phase-space methods - expressed through non-Gaussian convolutions of highly singular Glauber-Sudarshan quasiprobabilities - to dynamically monitor quantum coherence in polariton condensates with significantly enhanced coherence times. Via intensity- and time-resolved reconstructions of such phase-space functions from homodyne detection data, we probe the systems's resourcefulness for quantum information processing up to the nanosecond regime. Our experimental findings are confirmed through numerical simulations for which we develop an approach that renders established algorithms compatible with our methodology. In contrast to commonly applied phase-space functions, our distributions can be directly sampled from measured data, including uncertainties, and yield a simple operational measure of quantum coherence via the distribution's variance in phase. Therefore, we present a broadly applicable framework and a platform to explore time-dependent quantum phenomena and resources.
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Submitted 15 September, 2022;
originally announced September 2022.
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Effects of the linear polarization of polariton condensates in their propagation in codirectional couplers
Authors:
Elena Rozas,
Alexey Yulin,
Johannes Beierlein,
Sebastian Klembt,
Sven Höfling,
Oleg A. Egorov,
Ulf Peschel,
Ivan A. Shelykh,
Manuel Gundin,
Ignacio Robles-López,
M. Dolores Martín,
Luis Viña
Abstract:
We report on the linear polarization of polariton condensates in a codirectional coupler that allows evanescent coupling between adjacent waveguides. We observe polarization-dependent intensity oscillations in the output terminal of the coupler that we identify as the mode beating between the linear-polarized eigenmodes.
We report on the linear polarization of polariton condensates in a codirectional coupler that allows evanescent coupling between adjacent waveguides. We observe polarization-dependent intensity oscillations in the output terminal of the coupler that we identify as the mode beating between the linear-polarized eigenmodes.
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Submitted 31 May, 2021;
originally announced May 2021.
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Quantifying quantum coherence in polariton condensates
Authors:
Carolin Lüders,
Matthias Pukrop,
Elena Rozas,
Christian Schneider,
Sven Höfling,
Jan Sperling,
Stefan Schumacher,
Marc Aßmann
Abstract:
We theoretically and experimentally investigate quantum features of an interacting light-matter system from a multidisciplinary perspective, unifying approaches from semiconductor physics, quantum optics, and quantum information science. To this end, we quantify the amount of quantum coherence that results from the quantum superposition of Fock states, constituting a measure of the resourcefulness…
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We theoretically and experimentally investigate quantum features of an interacting light-matter system from a multidisciplinary perspective, unifying approaches from semiconductor physics, quantum optics, and quantum information science. To this end, we quantify the amount of quantum coherence that results from the quantum superposition of Fock states, constituting a measure of the resourcefulness of the produced state for modern quantum protocols. As an archetypal example of a hybrid light-matter interface, we study a polariton condensate and implement a numerical model to predict its properties. Our simulation is confirmed by our proof-of-concept experiment in which we measure and analyze the phase-space distributions of the emitted light. Specifically, we drive a polariton microcavity across the condensation threshold and observe the transition from an incoherent thermal state to a coherent state in the emission, thus confirming the build-up of quantum coherence in the condensate itself.
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Submitted 5 August, 2021; v1 submitted 4 March, 2021;
originally announced March 2021.
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On the remote coherence of polariton condensates in 1D microcavities: a photoluminescence study
Authors:
M. D. Martín,
E. Rozas,
C. Antón,
P. G. Savvidis,
L. Viña
Abstract:
In this manuscript we will gather clear experimental evidences of remote coherence between two polariton condensate droplets that have never overlapped in real space and discuss how these interferences in momentum space can be used to estimate the critical temperature for the BEC like transition.
In this manuscript we will gather clear experimental evidences of remote coherence between two polariton condensate droplets that have never overlapped in real space and discuss how these interferences in momentum space can be used to estimate the critical temperature for the BEC like transition.
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Submitted 21 August, 2020;
originally announced August 2020.
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Propagative oscillations in co-directional polariton waveguide couplers
Authors:
J. Beierlein,
E. Rozas,
O. A. Egorov,
M. Klaas,
A. Yulin,
H. Suchomel,
T. H. Harder,
M. Emmerling,
M. D. Martín,
I. A. Shelykh,
C. Schneider,
U. Peschel,
L. Viña,
S. Höfling,
S. Klembt
Abstract:
We report on novel exciton-polariton routing devices created to study and purposely guide light-matter particles in their condensate phase. In a co-directional coupling device, two waveguides are connected by a partially etched section which facilitates tunable coupling of the adjacent channels. This evanescent coupling of the two macroscopic wavefunctions in each waveguide reveals itself in real…
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We report on novel exciton-polariton routing devices created to study and purposely guide light-matter particles in their condensate phase. In a co-directional coupling device, two waveguides are connected by a partially etched section which facilitates tunable coupling of the adjacent channels. This evanescent coupling of the two macroscopic wavefunctions in each waveguide reveals itself in real space oscillations of the condensate. This Josephson-like oscillation has only been observed in coupled polariton traps so far. Here, we report on a similar coupling behavior in a controllable, propagative waveguide-based design. By controlling the gap width, channel length or the propagation energy, the exit port of the polariton flow can be chosen. This co-directional polariton device is a passive and scalable coupler element that can serve in compact, next generation logic architectures.
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Submitted 6 July, 2020; v1 submitted 20 April, 2020;
originally announced April 2020.
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Impact of the energetic landscape on polariton condensates propagation along a coupler
Authors:
E. Rozas,
J. Beierlein,
A. Yulin,
M. Klaas,
H. Suchomel,
O. Egorov,
I. A. Shelykh,
U. Peschel,
C. Schneider,
S. Klembt,
S. Höfling,
M. D. Martín,
L. Viña
Abstract:
Polariton condensates propagation is strongly dependent on the particular energy landscape the particles are moving upon, in which the geometry of the pathway laid for their movement plays a crucial role. Bends in the circuits trajectories affect the condensates speed and oblique geometries introduce an additional discretization of the polaritons momenta due to the mixing of short and long axis wa…
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Polariton condensates propagation is strongly dependent on the particular energy landscape the particles are moving upon, in which the geometry of the pathway laid for their movement plays a crucial role. Bends in the circuits trajectories affect the condensates speed and oblique geometries introduce an additional discretization of the polaritons momenta due to the mixing of short and long axis wavevectors on the propagating eigenvalues. In this work, we study the nature of the propagation of condensates along the arms of a polariton coupler, by a combination of time-resolved micro-tomography measurements and a theoretical model based on a mean field approximation where condensed polaritons are described by an equation for the slow varying amplitude of the polariton field coupled to an equation for the density of incoherent excitons.
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Submitted 21 April, 2020; v1 submitted 17 April, 2020;
originally announced April 2020.
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Direct observation of photonic Landau levels and helical edge states in strained honeycomb lattices
Authors:
O. Jamadi,
E. Rozas,
G. Salerno,
M. Milićević,
T. Ozawa,
I. Sagnes,
A. Lemaître,
L. Le Gratiet,
A. Harouri,
I. Carusotto,
J. Bloch,
A. Amo
Abstract:
We report the realization of a synthetic magnetic field for photons and polaritons in a honeycomb lattice of coupled semiconductor micropillars. A strong synthetic field is induced in both the s and p orbital bands by engineering a uniaxial hopping gradient in the lattice, giving rise to the formation of Landau levels at the Dirac points. We provide direct evidence of the sublattice symmetry break…
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We report the realization of a synthetic magnetic field for photons and polaritons in a honeycomb lattice of coupled semiconductor micropillars. A strong synthetic field is induced in both the s and p orbital bands by engineering a uniaxial hopping gradient in the lattice, giving rise to the formation of Landau levels at the Dirac points. We provide direct evidence of the sublattice symmetry breaking of the lowest-order Landau level wavefunction, a distinctive feature of synthetic magnetic fields. Our realization implements helical edge states in the gap between n=0 and n=1 Landau levels, experimentally demonstrating a novel way of engineering propagating edge states in photonic lattices. In light of recent advances in the enhancement of polariton-polariton nonlinearities, the Landau levels reported here are promising for the study of the interplay between pseudomagnetism and interactions in a photonic system.
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Submitted 5 January, 2021; v1 submitted 28 January, 2020;
originally announced January 2020.
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Determination of polariton condensates' critical temperature
Authors:
E. Rozas,
M. D. Martín,
C. Tejedor,
L. Viña,
G. Deligeorgis,
Z. Hatzopoulos,
P. G. Savvidis
Abstract:
We investigate the thermal robustness of traveling polariton condensates. We create remote condensates that have never been in contact, and study their interference in momentum space, when they travel with the same velocity, by means of time-resolved photoluminescence. We determine the condensed to thermal, uncondensed polariton fraction, which shows a gradual decay with increasing temperature, an…
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We investigate the thermal robustness of traveling polariton condensates. We create remote condensates that have never been in contact, and study their interference in momentum space, when they travel with the same velocity, by means of time-resolved photoluminescence. We determine the condensed to thermal, uncondensed polariton fraction, which shows a gradual decay with increasing temperature, and obtain the critical temperature for the Bose-Einstein-like condensate (BEC) phase transition. We tentatively compare our experimental findings with theoretical models, developed for atomic condensates, to describe the condensates' coherence fading with temperature.
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Submitted 22 April, 2020; v1 submitted 12 February, 2019;
originally announced February 2019.
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Counter-directional polariton coupler
Authors:
M. Klaas,
J. Beierlein,
E. Rozas,
S. Klembt,
H. Suchomel,
T. H. Harder,
K. Winkler,
M. Emmerling,
H. Flayac,
M. D. Martín,
L. Viña,
S. Höfling,
C. Schneider
Abstract:
We report on an on-chip routing device for propagating condensates of exciton-polaritons. This counterdirectional coupler implements signal control by a photonic microdisk potential, which couples two lithographically defined waveguides and reverses the condensate's propagation direction. By varying the structural sizes, we utilize the conjunction of the different dimensionalities to additionally…
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We report on an on-chip routing device for propagating condensates of exciton-polaritons. This counterdirectional coupler implements signal control by a photonic microdisk potential, which couples two lithographically defined waveguides and reverses the condensate's propagation direction. By varying the structural sizes, we utilize the conjunction of the different dimensionalities to additionally evidence the functionality of a polaritonic resonant tunnel diode. Furthermore, we investigate the ultra fast dynamics of the device via ps-resolved streak camera measurements, which is distinctive for the polariton platform. This scalable, all-directional coupler element is a central building block for compact non-linear on-chip photonic architectures.
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Submitted 11 February, 2019;
originally announced February 2019.
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Temperature dependence of the coherence in polariton condensates
Authors:
E. Rozas,
M. D. Martín,
C. Tejedor,
L. Viña,
G. Deligeorgis,
Z. Hatzopoulos,
P. G. Savvidis
Abstract:
We present a time-resolved experimental study of the temperature effect on the coherence of traveling polariton condensates. The simultaneous detection of their emission both in real- and reciprocal-space allows us to fully monitor the condensates' dynamics. We obtain fringes in reciprocal-space as a result of the interference between polariton wavepackets (WPs) traveling with the same speed. The…
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We present a time-resolved experimental study of the temperature effect on the coherence of traveling polariton condensates. The simultaneous detection of their emission both in real- and reciprocal-space allows us to fully monitor the condensates' dynamics. We obtain fringes in reciprocal-space as a result of the interference between polariton wavepackets (WPs) traveling with the same speed. The periodicity of these fringes is inversely proportional to the spatial distance between the interfering WPs. In a similar fashion, we obtain interference fringes in real-space when WPs traveling in opposite directions meet. The visibility of both real- and reciprocal-space interference fringes rapidly decreases with increasing temperature and vanishes. A theoretical description of the phase transition, considering the coexistence of condensed and non-condensed particles, for an out of equilibrium condensate such as ours is still missing. Yet a comparison with theories developed for atomic condensates allows us to infer a critical temperature for the BEC-like transition when the visibility goes to zero.
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Submitted 22 April, 2020; v1 submitted 17 October, 2017;
originally announced October 2017.
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Tension and stiffness of the hard sphere crystal-fluid interface
Authors:
Andreas Härtel,
Martin Oettel,
Roberto E. Rozas,
Stefan U. Egelhaaf,
Jürgen Horbach,
Hartmut Löwen
Abstract:
A combination of fundamental measure density functional theory and Monte Carlo computer simulation is used to determine the orientation-resolved interfacial tension and stiffness for the equilibrium hard-sphere crystal-fluid interface. Microscopic density functional theory is in quantitative agreement with simulations and predicts a tension of 0.66 kT/σ^2 with a small anisotropy of about 0.025 kT…
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A combination of fundamental measure density functional theory and Monte Carlo computer simulation is used to determine the orientation-resolved interfacial tension and stiffness for the equilibrium hard-sphere crystal-fluid interface. Microscopic density functional theory is in quantitative agreement with simulations and predicts a tension of 0.66 kT/σ^2 with a small anisotropy of about 0.025 kT and stiffnesses with e.g. 0.53 kT/σ^2 for the (001) orientation and 1.03 kT/σ^2 for the (111) orientation. Here kT is denoting the thermal energy and σthe hard sphere diameter. We compare our results with existing experimental findings.
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Submitted 26 June, 2012; v1 submitted 13 March, 2012;
originally announced March 2012.
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Computer simulation studies of finite-size broadening of solid-liquid interfaces: From hard spheres to nickel
Authors:
T. Zykova-Timan,
R. E. Rozas,
J. Horbach,
K. Binder
Abstract:
Using Molecular Dynamics (MD) and Monte Carlo (MC) simulations interfacial properties of crystal-fluid interfaces are investigated for the hard sphere system and the one-component metallic system Ni (the latter modeled by a potential of the embedded atom type). Different local order parameters are considered to obtain order parameter profiles for systems where the crystal phase is in coexistence…
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Using Molecular Dynamics (MD) and Monte Carlo (MC) simulations interfacial properties of crystal-fluid interfaces are investigated for the hard sphere system and the one-component metallic system Ni (the latter modeled by a potential of the embedded atom type). Different local order parameters are considered to obtain order parameter profiles for systems where the crystal phase is in coexistence with the fluid phase, separated by interfaces with (100) orientation of the crystal. From these profiles, the mean-squared interfacial width w^2 is extracted as a function of system size. We rationalize the prediction of capillary wave theory that w^2 diverges logarithmically with the lateral size of the system. We show that one can estimate the interfacial stiffness from the interfacial broadening, obtaining 0.5 k_B T/sigma^2 for hard spheres and 0.18 J/m^2 for Ni.
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Submitted 12 May, 2009;
originally announced May 2009.