Article
Quantum Science & Technology
Patrick Boegel, Alexander Wolf, Matthias Meister, Maxim A. Efremov
Summary: Motivated by the recent experimental realization of ultracold quantum gases in shell topology, we propose a straightforward implementation of matter-wave lensing techniques for shell-shaped Bose-Einstein condensates. This approach allows to significantly extend the free evolution time of the condensate shell after release from the trap and enables the study of novel quantum many-body effects on curved geometries. With both analytical and numerical methods we derive optimal parameters for realistic schemes to conserve the shell shape of the condensate for times up to hundreds of milliseconds.
QUANTUM SCIENCE AND TECHNOLOGY
(2023)
Article
Physics, Multidisciplinary
N. Dupont, F. Arrouas, L. Gabardos, N. Ombredane, J. Billy, B. Peaudecerf, D. Sugny, D. Guery-Odelin
Summary: We utilize quantum optimal control to manipulate the phase-space distribution of Bose-Einstein condensates in a one-dimensional optical lattice. By modulating the lattice position in a time-dependent manner, determined through optimal control theory, we prepare translated and squeezed Gaussian states, as well as superpositions of Gaussian states, in the phase space of each lattice site. These non-trivial states are fully reconstructed using maximum likelihood state tomography. As a practical application, we use our method to initialize the atomic wavefunction in an optimal Floquet-state superposition to enhance dynamical tunneling signals.
NEW JOURNAL OF PHYSICS
(2023)
Article
Multidisciplinary Sciences
Hon Wai Hana Lau, Jorn Davidsen, Christoph Simon
Summary: We propose a conservative Hamiltonian system with nonlocal hopping, which can exhibit chimera patterns. We also propose a possible experimentally realizable quantum system based on a two-component Bose-Einstein condensate with a spin-dependent optical lattice, where nonlocal spatial hopping over tens of lattice sites can be achieved and simulations suggest that chimera patterns should be observable in certain parameter regimes.
SCIENTIFIC REPORTS
(2023)
Article
Multidisciplinary Sciences
Xingran Xu, Tanjung Krisnanda, Timothy C. H. Liew
Summary: In this study, we investigate atoms in two periodic potentials induced by different lasers, one of which is coupled to a mechanical membrane via radiation pressure force. The dynamics of the atoms' position and momentum are treated classically, while the membrane, the cavity field, and the intrinsic two-level atoms are treated quantum mechanically. We find that the mean excitation of the three systems can be stable, periodically oscillating, or in a chaotic state depending on the strength of the coupling between them. We define regular, limit cycle, and chaotic phases and demonstrate how to achieve these phases by manipulating the field-membrane and field-atom coupling strengths. Additionally, we compute observable quantities such as position, momentum, and correlation functions that reflect the system's phase. Our proposal presents a new approach to generate and control limit cycle and chaotic phases in a well-established atom-optomechanics system.
SCIENTIFIC REPORTS
(2022)
Article
Physics, Multidisciplinary
Timon A. Hilker, Lena H. Dogra, Christoph Eigen, Robert P. Smith, Zoran Hadzibabic
Summary: The two sounds in a highly compressible fluid are investigated using an ultracold Bose gas. The results show that only one sound persists at different temperatures, which is consistent with the hydrodynamic theory.
PHYSICAL REVIEW LETTERS
(2022)
Article
Materials Science, Multidisciplinary
Jingjing Jin, Wei Han, Huifang Zhao, Wenyuan Liu
Summary: This study investigates the Moire superlattice structures generated by the interplay between vortex lattice and optical lattice in two-component Bose-Einstein condensates. The possible superlattice patterns under different twist angles are studied, as well as the relative shift of the Moire superlattices in two components of the condensates.
RESULTS IN PHYSICS
(2022)
Article
Optics
Thudiyangal Mithun, Kenichi Kasamatsu, Bishwajyoti Dey, Panayotis G. Kevrekidis
Summary: The study investigates quantum turbulence in miscible binary Bose-Einstein condensates and the formation of vortex-antidark structures under certain conditions. The interplay of parameter asymmetry and trap frequencies affects the dynamics of turbulent condensates, leading to the emergence of unique spectral features related to incompressible kinetic energy. Additionally, the impact of intercomponent interaction on like-signed vortex cluster formation in an elliptical steep-wall trap is examined, revealing the decay of clustered configurations due to intercomponent coupling.
Article
Optics
Lei Jin, Jia-Xin Peng, Qi-Zhang Yuan, Xun-Li Feng
Summary: This study investigates the various macroscopic quantum coherences in a spinning whispering-gallery-mode resonator system, revealing that the one-mode quantum coherences play a main role in two- and three-mode quantum coherences. The research also shows that quantum coherences in the spinning system are nonreciprocal, increasing monotonically with the rotating angular velocity when the driving direction of the laser field aligns with the rotation direction of the resonator.
Article
Materials Science, Multidisciplinary
Ekaterina Aladinskaia, Roman Cherbunin, Evgeny Sedov, Alexey Liubomirov, Kirill Kavokin, Evgeny Khramtsov, Mikhail Petrov, P. G. Savvidis, Alexey Kavokin
Summary: This study investigates the formation of exciton-polariton condensates in potlike traps created by optical pumping in a planar microcavity with embedded quantum wells. The experiment reveals the discrete spectrum of polariton eigenstates and demonstrates the control of these states through manipulating the shape and size of the trap and the spatial density distribution of the exciton reservoir.
Article
Optics
G. Vanhaele, P. Schlagheck
Summary: Theoretical investigation was conducted on the generation of microscopic atomic NOON states via collective tunneling of interacting ultracold bosonic atoms within a symmetric double-well potential. Periodic driving of the double well can substantially boost the tunneling process without altering its collective character, reducing the timescale to generate the NOON superposition. Resonance- and chaos-assisted tunneling are key mechanisms in this context.
Article
Physics, Multidisciplinary
Saeed Ghanbari
Summary: We introduce 3D permanent magnetic lattices for ultracold atoms and provide analytical expressions for the location of magnetic field minima and various physical quantities. The trap depths, modulation depths, and trap frequencies can be controlled by the bias field. Compared to optical lattices, the permanent magnetic lattices offer higher trap depths and trap frequencies, particularly between magnetic layers.
Article
Optics
Axel U. J. Lode, Rui Lin, Miriam Buettner, Luca Papariello, Camille Leveque, R. Chitra, Marios C. Tsatsos, Dieter Jaksch, Paolo Molignini
Summary: This study demonstrates how artificial neural networks can optimize the extraction of observables from single-shot images, accurately obtaining both one- and two-particle densities, as well as extracting momentum-space observables from real-space single-shot images. With this technique, reconfiguring the experimental setup only once to obtain training data may lead to a significant reduction in resources.
Article
Materials Science, Multidisciplinary
Qingbo Wang, Wenjing Zhao, Linghua Wen
Summary: The study reveals that spin-orbit coupling has a significant influence on the dynamics of kicked pseudo-spin-1/2 Bose-Einstein condensates under different conditions, mainly reflected in the different behaviors of density distribution and energy evolution.
RESULTS IN PHYSICS
(2021)
Article
Mathematics, Interdisciplinary Applications
Michele Modugno, E. Ya. Sherman
Summary: This study explores the dynamics of internal dynamical counter-pressure in three-dimensional Bose-Einstein condensates of cold atoms, finding that three-body interactions may lead to an internal pressure and repulsive potential in the condensate, which can affect the evolution of the entire condensate, including inhibiting collapse and causing explosions.
CHAOS SOLITONS & FRACTALS
(2022)
Article
Astronomy & Astrophysics
Decheng Ma, Chenglong Jia, Enrique Solano, Lucas Chibebe Celeri
Summary: The propagation of phonons in the presence of a particle sink with radial flow in a Bose-Einstein condensate is considered. It is found that due to the particle sink, which simulates a static acoustic black hole, the phonon experiences significant spacetime curvature at a considerable distance from the sink. The trajectory of the phonons is bent after passing by the particle sink, simulating the gravitational lensing effect in a Bose-Einstein condensate. Possible experimental implementations are discussed.
Article
Physics, Applied
Raphael Holzinger, Maria Moreno-Cardoner, Helmut Ritsch
Summary: Regular arrays of two-level emitters within distances smaller than the transition wavelength collectively scatter, absorb, and emit photons, exhibiting a highly nonlinear response. Utilizing strong inter-particle dipole coupling allows for the implementation of nanoscale non-classical light sources. Experimental results show that fields emitted perpendicular to the illumination direction exhibit strong directional confinement with genuine quantum properties, such as antibunching.
APPLIED PHYSICS LETTERS
(2021)
Article
Optics
Elias Starchl, Helmut Ritsch
Summary: In this study, we investigate whether a full quantum representation of dynamics leads to a higher probability of finding the desired ground state compared to a classical mean field approximation. The results show that there is a parameter region where quantum annealing is highly successful, while the semiclassical approach largely fails. The importance of entanglement in approaching the optimal solution is also demonstrated.
JOURNAL OF PHYSICS B-ATOMIC MOLECULAR AND OPTICAL PHYSICS
(2022)
Article
Optics
Maria Moreno-Cardoner, Raphael Holzinger, Helmut Ritsch
Summary: Nanoscopic arrays of quantum emitters can be used to create highly efficient single photon antennas by adding an absorptive impurity as an energy dump in the center of a ring shaped polygon. A nonagon shape exhibits the highest absorption efficiency, thanks to the matching coupling strengths between the emitters and the center to ring coupling. The antenna ring acts like a parabolic mirror, concentrating incoming radiation at its center.
Article
Optics
Christoph Hotter, David Plankensteiner, Georgy Kazakov, Helmut Ritsch
Summary: The study presents a theoretical analysis of a realistic multi-level implementation to achieve inversion with minimal perturbations. A useful operating regime is identified where frequency shifts are small and controllable, weakly perturbing the clock transition.
Article
Quantum Science & Technology
David Plankensteiner, Christoph Hotter, Helmut Ritsch
Summary: A full quantum mechanical treatment of open quantum systems is often limited by the size of the underlying Hilbert space. In this paper, the authors propose an open-source framework that automates the cumulant expansion approach for truncating the infinite set of operator product equations. The framework is showcased in several example problems, demonstrating its usefulness.
Article
Nanoscience & Nanotechnology
Philipp Aumann, Maximilian Prilmueller, Florian Kappe, Laurin Ostermann, Dan Dalacu, Philip J. Poole, Helmut Ritsch, Wolfgang Lechner, Gregor Weihs
Summary: This paper introduces the preparation of time-bin entangled photon pairs by resonantly exciting the biexciton state in a quantum dot using coherent pulses. The implementation of this scheme in a dot embedded in an InP nanowire is analyzed using an effective three-level open system master equation. The resulting entanglement and optimal operating conditions are predicted based on parameters extracted from experimental data.
Article
Physics, Multidisciplinary
R. Holzinger, R. Gutierrez-Jauregui, T. Honigl-Decrinis, G. Kirchmair, A. Asenjo-Garcia, H. Ritsch
Summary: This study identifies a new class of dark states that can efficiently store and read out photons, and proposes an experimental method using superconducting transmon qubits on a chip, which features fast preparation and precise manipulation.
PHYSICAL REVIEW LETTERS
(2022)
Article
Multidisciplinary Sciences
Victor Helson, Timo Zwettler, Farokh Mivehvar, Elvia Colella, Kevin Roux, Hideki Konishi, Helmut Ritsch, Jean-Philippe Brantut
Summary: A density wave (DW) is a type of long-range order in quantum matter that is associated with self-organization into a crystalline structure. The interplay of DW order with superfluidity presents a significant theoretical challenge. In this study, a tunable quantum Fermi gas with both strong, contact interactions and photon-mediated, spatially structured long-range interactions in an optical cavity is realized. The DW order is stabilized in the system above a critical long-range interaction strength, which is identified through superradiant light-scattering properties. The experimental setup provides a fully tunable and microscopically controllable platform for studying the interplay of superfluidity and DW order.
Article
Physics, Multidisciplinary
Karol Gietka, Helmut Ritsch
Summary: We predict that exploiting spin-orbit coupling in a harmonically trapped spinor quantum gas can lead to scaling of the optimal measurement precision beyond the Heisenberg scaling. We show that quadratic scaling with the number of atoms can be facilitated via squeezed center-of-mass excitations of the atomic motion using 1D spin-orbit coupled fermions or strongly interacting bosons (Tonks-Girardeau gas). Based on predictions derived from analytic calculations of the corresponding quantum Fisher information, we then introduce a protocol which overcomes the Heisenberg scaling (and limit) with the help of a tailored excited and entangled many-body state of a noninteracting Bose-Einstein condensate. We identify corresponding optimal measurements and argue that even finite temperature as a source of decoherence is, in principle, rather favorable for the obtainable precision scaling.
PHYSICAL REVIEW LETTERS
(2023)
Article
Chemistry, Multidisciplinary
Verena Scheil, Raphael Holzinger, Maria Moreno-Cardoner, Helmut Ritsch
Summary: A ring of sub-wavelength spaced dipole-coupled quantum emitters has extraordinary optical properties and can create extremely sub-radiant collective eigenmodes similar to an optical resonator. Stacked multi-ring geometries, particularly double rings, allow for significantly darker and better confined collective excitations. The three-ring geometry found in natural light-harvesting complexes is close to a critical value for efficient and fast coherent inter-ring transport.
Article
Physics, Multidisciplinary
Anna Bychek, Helmut Ritsch
Summary: The implementation of a superradiant laser as an active frequency standard is predicted to provide better short-term stability and robustness. A new scenario of using bichromatic coherent pumping on a trapped cold atomic gas inside a single-mode cavity is proposed to create continuous gain.
NEW JOURNAL OF PHYSICS
(2023)
Article
Physics, Multidisciplinary
Arkadiusz Kosior, Helmut Ritsch, Farokh Mivehvar
Summary: This article investigates the naturally engineered dynamical gauge fields by photons in composite, neutral quantum gas-cavity systems using suitable atom-photon interactions. The study reveals a minimal dynamical flux-lattice model, with various nonequilibrium dynamical phases including limit-cycle and chaotic phases.
Article
Physics, Multidisciplinary
Christoph Hotter, Laurin Ostermann, Helmut Ritsch
Summary: Large atomic ensembles coupled to a single optical resonator mode can exhibit strongly enhanced or suppressed collective emission by controlling the excitation phase. Using the Tavis-Cummings model, we report previously unobserved phenomena. By employing a second order cumulant expansion, we predict that a evenly excited atomic ensemble distributed along the cavity mode can be extremely subradiant when the average excitation is below 50%, but shows pulsed emission for inversion. These properties enable the implementation of an efficient cavity-enhanced Ramsey probing for atomic clock transitions with fast readout and minimal heating.
PHYSICAL REVIEW RESEARCH
(2023)
Article
Physics, Multidisciplinary
R. Holzinger, S. A. Oh, M. Reitz, H. Ritsch, C. Genes
Summary: This study provides analytical and numerical results on the modification of super- and subradiance in molecular emitters, taking into account the excitation of vibrational degrees of freedom. It reveals that molecular rings can be operated as platforms for the preparation of long-lived dark superposition states aided by vibrational relaxation.
PHYSICAL REVIEW RESEARCH
(2022)
Article
Optics
D. A. Ivanov, T. Yu Ivanova, S. F. Caballero-Benitez, I. B. Mekhov
Summary: The paper introduces a new method of controlling quantum systems by shifting the paradigm from controlling quantum states to controlling phase transitions. It demonstrates that feedback can tune the universality class of phase transitions by modifying critical exponents, expands previous treatments of the Dicke model, and considers both linearized and nonlinear models of spin ensembles. The tunability of quantum fluctuations near critical points through feedbacks of nontrivial shapes is explained by analyzing fluctuation spectra and system behavior at single quantum trajectories.
