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Experimental observation of strong field stabilization
Authors:
Anna R. Dardia,
Spencer Walker,
Yifei Bai,
Petros Kousis,
Alexandra S. Landsman,
David M. Weld
Abstract:
Bound quantum states such as atoms can be torn apart by strong oscillating fields. A natural expectation is that stronger fields lead to more certain destruction. In contradiction to this intuition, some theories predict a striking reversal: that as the field intensity is raised above some threshold, bound state wavefunctions can spatially bifurcate and become increasingly stable with increasing f…
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Bound quantum states such as atoms can be torn apart by strong oscillating fields. A natural expectation is that stronger fields lead to more certain destruction. In contradiction to this intuition, some theories predict a striking reversal: that as the field intensity is raised above some threshold, bound state wavefunctions can spatially bifurcate and become increasingly stable with increasing field intensity. This ``strong field stabilization'' was predicted decades ago in the context of atoms in pulsed laser fields, but has resisted experimental observation due to extreme laser intensity requirements and theoretical controversy. We report the experimental observation of strong-field stabilization of a ground state, using trapped neutral atoms to emulate the dynamics of atomic electrons in an extremely strong laser field. We directly image the predicted wavepacket bifurcation, measure an ionization rate non-monotonic in field amplitude, and map out the regime of stabilization as a function of laser pulse parameters. We observe that stabilization persists down to surprisingly low drive frequencies, near and below the scale of the lowest-energy excitations of the bound state. These results confirm and extend a long-standing prediction of extreme quantum dynamics, and showcase a complementary tool for probing strong-field phenomena near and beyond the frontier of current laser technology.
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Submitted 17 July, 2026; v1 submitted 29 May, 2026;
originally announced June 2026.
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A matter-wave Fabry-Pérot cavity in the ultrastrong driving regime
Authors:
Jeremy L. Tanlimco,
Eber Nolasco-Martinez,
Xiao Chai,
S. Nicole Halawani,
Eric Zhu,
Ivar Martin,
David M. Weld
Abstract:
When the length of an optical cavity is modulated, theory predicts exponential concentration of energy around particular space-time trajectories. Viewed stroboscopically, photons in such a driven cavity propagate as if in a curved spacetime, with black hole and white hole event horizons corresponding to unstable and stable fixed points of the evolution. Such phenomena have resisted direct experime…
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When the length of an optical cavity is modulated, theory predicts exponential concentration of energy around particular space-time trajectories. Viewed stroboscopically, photons in such a driven cavity propagate as if in a curved spacetime, with black hole and white hole event horizons corresponding to unstable and stable fixed points of the evolution. Such phenomena have resisted direct experimental realization due to the difficulty of relativistically accelerating massive cavity mirrors. We report results of an experiment which overcomes this limitation by exchanging the roles of light and matter. A matter wave endowed with quasi-relativistic dispersion is confined between two barriers made of light, one of which is periodically translated at speeds comparable to the matter wave group velocity. In this strongly-modulated cavity we observe the emergence of the predicted bright and dark fixed point trajectories, and demonstrate that changing the modulation waveform can vary the number of fixed points and exchange their stability character. We observe signatures of nontrivial dynamics beyond those predicted for photons, and attribute them to residual curvature in the dispersion relation. In addition to experimentally realizing and characterizing cavity dynamics in the ultra-strong driving regime, these results point the way to implementations of related dynamics in electro-optic materials, with potential applications in pulse generation and signal compression.
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Submitted 28 January, 2026;
originally announced January 2026.
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Continuously trapped matter-wave interferometry in magic Floquet-Bloch band structures
Authors:
Xiao Chai,
Eber Nolasco-Martinez,
Xuanwei Liang,
Jeremy L. Tanlimco,
E. Quinn Simmons,
Eric Zhu,
Roshan Sajjad,
Hector Mas,
S. Nicole Halawani,
Alec Cao,
David M. Weld
Abstract:
Trapped matter-wave interferometry offers the promise of compact high-precision local force sensing. However, noise in the trap itself can introduce new systematic errors which are absent in traditional free-fall interferometers. We describe and demonstrate an intrinsically noise-tolerant Floquet-engineered platform for continuously trapped atom interferometry. A non-interacting degenerate quantum…
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Trapped matter-wave interferometry offers the promise of compact high-precision local force sensing. However, noise in the trap itself can introduce new systematic errors which are absent in traditional free-fall interferometers. We describe and demonstrate an intrinsically noise-tolerant Floquet-engineered platform for continuously trapped atom interferometry. A non-interacting degenerate quantum gas undergoes position-space Bloch oscillations through an amplitude-modulated optical lattice, whose resulting Floquet-Bloch band structure includes Landau-Zener beamsplitters and Bragg mirrors, forming the components of a Mach-Zehnder interferometric force sensor. We identify, realize, and experimentally characterize magic band structures, analogous to the magic wavelengths employed in optical lattice clocks, for which the interferometric phase is insensitive to lattice intensity noise. We leverage the intrinsic programmability of the Floquet band synthesis approach to demonstrate a variety of interferometer structures, highlighting the potential of this technique for quantum force sensors which are tunable, compact, simple, and robust.
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Submitted 22 August, 2025; v1 submitted 13 June, 2025;
originally announced June 2025.
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Robust high-temperature atomic beam source with a microcapillary array
Authors:
Peter Dotti,
Xiao Chai,
Jeremy L. Tanlimco,
Ethan Q. Simmons,
David M. Weld
Abstract:
We present a new design for a directed high-flux high-temperature atomic vapor source for use in atomic physics experiments conducted under vacuum. An externally heated nozzle made of an array of stainless steel microcapillaries produces a collimated atomic beam. Welded stainless steel construction allows for operation at high source temperatures without exposing delicate conflat vacuum flanges to…
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We present a new design for a directed high-flux high-temperature atomic vapor source for use in atomic physics experiments conducted under vacuum. An externally heated nozzle made of an array of stainless steel microcapillaries produces a collimated atomic beam. Welded stainless steel construction allows for operation at high source temperatures without exposing delicate conflat vacuum flanges to thermal stress, greatly enhancing robustness compared to previously published designs. We report in operando performance measurements of an atomic beam of lithium at various operating temperatures.
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Submitted 10 February, 2025;
originally announced February 2025.
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Integrated Mode-Hop-Free Tunable Lasers at 780 nm for Chip-Scale Classical and Quantum Photonic Applications
Authors:
Joshua E. Castro,
Eber Nolasco-Martinez,
Paolo Pintus,
Zeyu Zhang,
Boqiang Shen,
Theodore Morin,
Lillian Thiel,
Trevor J. Steiner,
Nicholas Lewis,
Sahil D. Patel,
John E. Bowers,
David M. Weld,
Galan Moody
Abstract:
In the last decade, remarkable advances in integrated photonic technologies have enabled table-top experiments and instrumentation to be scaled down to compact chips with significant reduction in size, weight, power consumption, and cost. Here, we demonstrate an integrated continuously tunable laser in a heterogeneous gallium arsenide-on-silicon nitride (GaAs-on-SiN) platform that emits in the far…
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In the last decade, remarkable advances in integrated photonic technologies have enabled table-top experiments and instrumentation to be scaled down to compact chips with significant reduction in size, weight, power consumption, and cost. Here, we demonstrate an integrated continuously tunable laser in a heterogeneous gallium arsenide-on-silicon nitride (GaAs-on-SiN) platform that emits in the far-red radiation spectrum near 780 nm, with 20 nm tuning range, <6 kHz intrinsic linewidth, and a >40 dB side-mode suppression ratio. The GaAs optical gain regions are heterogeneously integrated with low-loss SiN waveguides. The narrow linewidth lasing is achieved with an extended cavity consisting of a resonator-based Vernier mirror and a phase shifter. Utilizing synchronous tuning of the integrated heaters, we show mode-hop-free wavelength tuning over a range larger than 100 GHz (200 pm). To demonstrate the potential of the device, we investigate two illustrative applications: (i) the linear characterization of a silicon nitride microresonator designed for entangled-photon pair generation, and (ii) the absorption spectroscopy and locking to the D1 and D2 transition lines of 87-Rb. The performance of the proposed integrated laser holds promise for a broader spectrum of both classical and quantum applications in the visible range, encompassing communication, control, sensing, and computing.
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Submitted 22 July, 2024;
originally announced July 2024.
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Tunably-polarized driving light controls the phase diagram of 1D quasicrystals and 2D quantum Hall matter
Authors:
Yifei Bai,
David M. Weld
Abstract:
The well-known mapping between 1D quasiperiodic systems and 2D integer quantum Hall matter can also be applied in the presence of driving. Here we explore the effect of time-varying electric fields on the transport properties and phase diagram of Harper-Hofstadter materials. We consider light of arbitrary polarization illuminating a 2D electron gas at high magnetic field; this system maps to a 1D…
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The well-known mapping between 1D quasiperiodic systems and 2D integer quantum Hall matter can also be applied in the presence of driving. Here we explore the effect of time-varying electric fields on the transport properties and phase diagram of Harper-Hofstadter materials. We consider light of arbitrary polarization illuminating a 2D electron gas at high magnetic field; this system maps to a 1D quasicrystal subjected to simultaneous phasonic and dipolar driving. We show that this generalized driving generates a tessellated phase diagram featuring a nested duality-protected pattern of metal-insulator transitions. Circularly or elliptically polarized light can create an extended critical phase, opening up a new route to achieving wavefunction multifractality without fine-tuning to a critical point. We describe in detail a path to experimental realization of these phenomena using lattice-trapped ultracold atoms.
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Submitted 18 March, 2025; v1 submitted 3 June, 2024;
originally announced June 2024.
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Measuring a localization phase diagram controlled by the interplay of disorder and driving
Authors:
Peter Dotti,
Yifei Bai,
Toshihiko Shimasaki,
Anna R. Dardia,
David M. Weld
Abstract:
The interplay of various localizing mechanisms is a central topic of modern condensed matter physics. In this work we experimentally explore the interplay between quasiperiodic disorder and periodic driving, each of which in isolation is capable of driving a metal-insulator phase transition. Using a 1D quasiperiodic cold-atom chain we measure transport across the full phase diagram varying both dr…
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The interplay of various localizing mechanisms is a central topic of modern condensed matter physics. In this work we experimentally explore the interplay between quasiperiodic disorder and periodic driving, each of which in isolation is capable of driving a metal-insulator phase transition. Using a 1D quasiperiodic cold-atom chain we measure transport across the full phase diagram varying both drive strength and quasidisorder strength. We observe lobes of metallic phases bounded by quantum phase transitions which depend on both drive and disorder. While these observations are broadly consistent with expectations from a high-drive-frequency theoretical model, we also observe clear departures from the predictions of this model, including anomalous changes in localization behavior at lower drive frequency. We demonstrate experimentally and theoretically that understanding the full measured phase diagram requires an extension to commonly-used approximate theories of Floquet matter.
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Submitted 15 November, 2024; v1 submitted 31 May, 2024;
originally announced June 2024.
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Reversible phasonic control of a quantum phase transition in a quasicrystal
Authors:
Toshihiko Shimasaki,
Yifei Bai,
H. Esat Kondakci,
Peter Dotti,
Jared E. Pagett,
Anna R. Dardia,
Max Prichard,
André Eckardt,
David M. Weld
Abstract:
Periodic driving can tune the quasistatic properties of quantum matter. A well-known example is the dynamical modification of tunneling by an oscillating electric field. Here we show experimentally that driving the phasonic degree of freedom of a cold-atom quasicrystal can continuously tune the effective quasi-disorder strength, reversibly toggling a localization-delocalization quantum phase trans…
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Periodic driving can tune the quasistatic properties of quantum matter. A well-known example is the dynamical modification of tunneling by an oscillating electric field. Here we show experimentally that driving the phasonic degree of freedom of a cold-atom quasicrystal can continuously tune the effective quasi-disorder strength, reversibly toggling a localization-delocalization quantum phase transition. Measurements agree with fit-parameter-free theoretical predictions, and illuminate a fundamental connection between Aubry-André localization in one dimension and dynamic localization in the associated two-dimensional Harper-Hofstadter model. These results open up new experimental possibilities for dynamical coherent control of quantum phase transitions.
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Submitted 1 December, 2023;
originally announced December 2023.
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Analog simulation of high harmonic generation in atoms
Authors:
Javier Argüello-Luengo,
Javier Rivera-Dean,
Philipp Stammer,
Andrew S. Maxwell,
David M. Weld,
Marcelo F. Ciappina,
Maciej Lewenstein
Abstract:
The demanding experimental access to the ultrafast dynamics of materials challenges our understanding of their electronic response to applied strong laser fields. For this purpose, trapped ultracold atoms with highly controllable potentials have become an enabling tool to describe phenomena in a scenario where some effects are more easily accessible and twelve orders of magnitude slower. In this w…
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The demanding experimental access to the ultrafast dynamics of materials challenges our understanding of their electronic response to applied strong laser fields. For this purpose, trapped ultracold atoms with highly controllable potentials have become an enabling tool to describe phenomena in a scenario where some effects are more easily accessible and twelve orders of magnitude slower. In this work, we introduce a mapping between the parameters of attoscience platform and atomic cloud simulators, and propose an experimental protocol to access the emission spectrum of high harmonic generation, a regime that has so far been elusive to cold atom simulation. As we illustrate, the benchmark offered by these simulators can provide new insights on the conversion efficiency of extended and short nuclear potentials, as well as the response to applied elliptical polarized fields or ultrashort few-cycle pulses.
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Submitted 25 February, 2024; v1 submitted 20 August, 2023;
originally announced August 2023.
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Thermodynamic engine with a quantum degenerate working fluid
Authors:
Ethan Q. Simmons,
Roshan Sajjad,
Kimberlee Keithley,
Hector Mas,
Jeremy L. Tanlimco,
Eber Nolasco-Martinez,
Yifei Bai,
Glenn H. Fredrickson,
David M. Weld
Abstract:
Can quantum mechanical thermodynamic engines outperform their classical counterparts? To address one aspect of this question, we experimentally realize and characterize an isentropic thermodynamic engine that uses a Bose-condensed working fluid. In this engine, an interacting quantum degenerate gas of bosonic lithium is subjected to trap compression and relaxation strokes interleaved with strokes…
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Can quantum mechanical thermodynamic engines outperform their classical counterparts? To address one aspect of this question, we experimentally realize and characterize an isentropic thermodynamic engine that uses a Bose-condensed working fluid. In this engine, an interacting quantum degenerate gas of bosonic lithium is subjected to trap compression and relaxation strokes interleaved with strokes strengthening and weakening interparticle interactions. We observe a significant enhancement in efficiency and power when using a Bose-condensed working fluid, compared to the case of a non-degenerate thermal gas. We demonstrate reversibility, and measure power and efficiency as a function of engine parameters including compression ratio and cycle time. Results agree quantitatively with interacting finite temperature field-theoretic simulations that closely replicate the length and energy scales of the working fluid.
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Submitted 20 April, 2023; v1 submitted 2 April, 2023;
originally announced April 2023.
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Anomalous localization and multifractality in a kicked quasicrystal
Authors:
Toshihiko Shimasaki,
Max Prichard,
H. Esat Kondakci,
Jared Pagett,
Yifei Bai,
Peter Dotti,
Alec Cao,
Tsung-Cheng Lu,
Tarun Grover,
David M. Weld
Abstract:
Multifractal states offer a "third way" for quantum matter, neither fully localized nor ergodic, exhibiting singular continuous spectra, self-similar wavefunctions, and transport and entanglement scaling exponents intermediate between extended and localized states. While multifractality in equilibrium systems generally requires fine-tuning to a critical point, externally driven quantum matter can…
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Multifractal states offer a "third way" for quantum matter, neither fully localized nor ergodic, exhibiting singular continuous spectra, self-similar wavefunctions, and transport and entanglement scaling exponents intermediate between extended and localized states. While multifractality in equilibrium systems generally requires fine-tuning to a critical point, externally driven quantum matter can exhibit multifractal states with no equilibrium counterpart. We report the experimental observation of multifractal matter and anomalous localization in a kicked Aubry-André-Harper quasicrystal. Our cold-atom realization of this previously-unexplored model is enabled by apodized Floquet engineering techniques which expand the accessible phase diagram by five orders of magnitude. This kicked quantum quasicrystal exhibits a rich phase diagram including not only fully localized and fully delocalized phases but also an extended region comprising an intricate nested pattern of localized, delocalized, and multifractal states. Mapping transport properties throughout the phase diagram, we observe disorder-driven re-entrant delocalization and sub-ballistic transport, and present a theoretical explanation of these phenomena based on eigenstate multifractality. These results open up the exploration of new states of matter characterized by an intricate interplay of fractal structure and quantum dynamics.
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Submitted 3 May, 2022; v1 submitted 17 March, 2022;
originally announced March 2022.
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Transport controlled by Poincaré orbit topology in a driven inhomogeneous lattice gas
Authors:
Alec Cao,
Roshan Sajjad,
Ethan Q. Simmons,
Cora J. Fujiwara,
Toshihiko Shimasaki,
David M. Weld
Abstract:
In periodic quantum systems which are both homogeneously tilted and driven, the interplay between drive and Bloch oscillations controls transport dynamics. Using a quantum gas in a modulated optical lattice, we show experimentally that inhomogeneity of the applied force leads to a rich new variety of dynamical behaviors controlled by the drive phase, from self-parametrically-modulated Bloch epicyc…
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In periodic quantum systems which are both homogeneously tilted and driven, the interplay between drive and Bloch oscillations controls transport dynamics. Using a quantum gas in a modulated optical lattice, we show experimentally that inhomogeneity of the applied force leads to a rich new variety of dynamical behaviors controlled by the drive phase, from self-parametrically-modulated Bloch epicycles to adaptive driving of transport against a force gradient to modulation-enhanced monopole modes. Matching experimental observations to fit-parameter-free numerical predictions of time-dependent band theory, we show that these phenomena can be quantitatively understood as manifestations of an underlying inhomogeneity-induced phase space structure, in which topological classification of stroboscopic Poincaré orbits controls the transport dynamics.
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Submitted 2 June, 2020;
originally announced June 2020.
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Non-exponential decay in Floquet-Bloch bands
Authors:
Alec Cao,
Cora J. Fujiwara,
Roshan Sajjad,
Ethan Q. Simmons,
Eva Lindroth,
David M. Weld
Abstract:
Exponential decay laws describe systems ranging from unstable nuclei to fluorescent molecules, in which the probability of jumping to a lower-energy state in any given time interval is static and history-independent. These decays, involving only a metastable state and fluctuations of the quantum vacuum, are the most fundamental nonequilibrium process, and provide a microscopic model for the origin…
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Exponential decay laws describe systems ranging from unstable nuclei to fluorescent molecules, in which the probability of jumping to a lower-energy state in any given time interval is static and history-independent. These decays, involving only a metastable state and fluctuations of the quantum vacuum, are the most fundamental nonequilibrium process, and provide a microscopic model for the origins of irreversibility. Despite the fact that the apparently universal exponential decay law has been precisely tested in a variety of physical systems, it is a surprising truth that quantum mechanics requires that spontaneous decay processes have non-exponential time dependence at both very short and very long times. Cold-atom experiments both classic and recent have proven to be powerful probes of fundamental decay processes; in this paper, we propose the use of Bose condensates in Floquet-Bloch bands as a probe of long-time non-exponential decay in single isolated emitters. We identify a range of parameters that should enable observation of long-time deviations, and experimentally demonstrate a key element of the scheme: tunable decay between quasienergy bands in a driven optical lattice.
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Submitted 7 February, 2020;
originally announced February 2020.
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Phasonic Spectroscopy of a Quantum Gas in a Quasicrystalline Lattice
Authors:
Shankari V. Rajagopal,
Toshihiko Shimasaki,
Peter Dotti,
Mantas Račiūnas,
Ruwan Senaratne,
Egidijus Anisimovas,
André Eckardt,
David M. Weld
Abstract:
Phasonic degrees of freedom are unique to quasiperiodic structures, and play a central role in poorly-understood properties of quasicrystals from excitation spectra to wavefunction statistics to electronic transport. However, phasons are challenging to access dynamically in the solid state due to their complex long-range character and the effects of disorder and strain. We report phasonic spectros…
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Phasonic degrees of freedom are unique to quasiperiodic structures, and play a central role in poorly-understood properties of quasicrystals from excitation spectra to wavefunction statistics to electronic transport. However, phasons are challenging to access dynamically in the solid state due to their complex long-range character and the effects of disorder and strain. We report phasonic spectroscopy of a quantum gas in a one-dimensional quasicrystalline optical lattice. We observe that strong phasonic driving produces a nonperturbative high-harmonic plateau strikingly different from the effects of standard dipolar driving. Tuning the potential from crystalline to quasicrystalline, we identify spectroscopic signatures of quasiperiodicity and interactions and map the emergence of a multifractal energy spectrum, opening a path to direct imaging of the Hofstadter butterfly.
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Submitted 28 October, 2019; v1 submitted 11 September, 2019;
originally announced September 2019.
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Quantifying and controlling prethermal nonergodicity in interacting Floquet matter
Authors:
Kevin Singh,
Cora J. Fujiwara,
Zachary A. Geiger,
Ethan Q. Simmons,
Mikhail Lipatov,
Alec Cao,
Peter Dotti,
Shankari V. Rajagopal,
Ruwan Senaratne,
Toshihiko Shimasaki,
Markus Heyl,
André Eckardt,
David M. Weld
Abstract:
The use of periodic driving for synthesizing many-body quantum states depends crucially on the existence of a prethermal regime, which exhibits drive-tunable properties while forestalling the effects of heating. This motivates the search for direct experimental probes of the underlying localized nonergodic nature of the wave function in this metastable regime. We report experiments on a many-body…
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The use of periodic driving for synthesizing many-body quantum states depends crucially on the existence of a prethermal regime, which exhibits drive-tunable properties while forestalling the effects of heating. This motivates the search for direct experimental probes of the underlying localized nonergodic nature of the wave function in this metastable regime. We report experiments on a many-body Floquet system consisting of atoms in an optical lattice subjected to ultrastrong sign-changing amplitude modulation. Using a double-quench protocol we measure an inverse participation ratio quantifying the degree of prethermal localization as a function of tunable drive parameters and interactions. We obtain a complete prethermal map of the drive-dependent properties of Floquet matter spanning four square decades of parameter space. Following the full time evolution, we observe sequential formation of two prethermal plateaux, interaction-driven ergodicity, and strongly frequency-dependent dynamics of long-time thermalization. The quantitative characterization of the prethermal Floquet matter realized in these experiments, along with the demonstration of control of its properties by variation of drive parameters and interactions, opens a new frontier for probing far-from-equilibrium quantum statistical mechanics and new possibilities for dynamical quantum engineering.
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Submitted 27 August, 2019; v1 submitted 14 September, 2018;
originally announced September 2018.
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Transport in Floquet-Bloch bands
Authors:
C. J. Fujiwara,
Kevin Singh,
Zachary A. Geiger,
Ruwan Senaratne,
Shankari Rajagopal,
Mikhail Lipatov,
David M. Weld
Abstract:
We report Floquet band engineering of long-range transport and direct imaging of Floquet-Bloch bands in an amplitude-modulated optical lattice. In one variety of Floquet-Bloch band we observe tunable rapid long-range high-fidelity transport of a Bose condensate across thousands of lattice sites. Quenching into an opposite-parity Floquet-hybridized band allows Wannier-Stark localization to be contr…
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We report Floquet band engineering of long-range transport and direct imaging of Floquet-Bloch bands in an amplitude-modulated optical lattice. In one variety of Floquet-Bloch band we observe tunable rapid long-range high-fidelity transport of a Bose condensate across thousands of lattice sites. Quenching into an opposite-parity Floquet-hybridized band allows Wannier-Stark localization to be controllably turned on and off using modulation. A central result of this work is the use of transport dynamics to demonstrate direct imaging of a Floquet-Bloch band structure. These results demonstrate that transport in dynamical Floquet-Bloch bands can be mapped to transport in quasi-static effective bands, opening a path to cold atom quantum emulation of ultrafast multi-band electronic dynamics.
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Submitted 8 February, 2019; v1 submitted 20 June, 2018;
originally announced June 2018.
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Observation and uses of position-space Bloch oscillations in an ultracold gas
Authors:
Zachary A. Geiger,
Kurt M. Fujiwara,
Kevin Singh,
Ruwan Senaratne,
Shankari V. Rajagopal,
Mikhail Lipatov,
Toshihiko Shimasaki,
Rodislav Driben,
Vladimir V. Konotop,
Torsten Meier,
David M. Weld
Abstract:
We report the direct observation and characterization of position-space Bloch oscillations using an ultracold gas in a tilted optical lattice. While Bloch oscillations in momentum space are a common feature of optical lattice experiments, the real-space center-of-mass dynamics are typically too small to resolve. Tuning into the regime of rapid tunneling and weak force, we observe real-space Bloch…
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We report the direct observation and characterization of position-space Bloch oscillations using an ultracold gas in a tilted optical lattice. While Bloch oscillations in momentum space are a common feature of optical lattice experiments, the real-space center-of-mass dynamics are typically too small to resolve. Tuning into the regime of rapid tunneling and weak force, we observe real-space Bloch oscillation amplitudes of hundreds of lattice sites, in both ground and excited bands. We demonstrate two unique capabilities enabled by tracking of Bloch dynamics in position space: measurement of the full position-momentum phase-space evolution during a Bloch cycle, and direct imaging of the lattice band structure. These techniques, along with the ability to exert long-distance coherent control of quantum gases without modulation, may open up new possibilities for quantum control and metrology.
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Submitted 6 March, 2018;
originally announced March 2018.
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Quantum Simulation of Ultrafast Dynamics Using Trapped Ultracold Atoms
Authors:
Ruwan Senaratne,
Shankari V. Rajagopal,
Toshihiko Shimasaki,
Peter E. Dotti,
Kurt M. Fujiwara,
Kevin Singh,
Zachary A. Geiger,
David M. Weld
Abstract:
Ultrafast electronic dynamics are typically studied using pulsed lasers. We demonstrate a complementary experimental approach: quantum simulation of ultrafast dynamics using trapped ultracold atoms. Counter-intuitively, this technique emulates some of the fastest processes in atomic physics with some of the slowest, leading to a temporal magnification factor of up to twelve orders of magnitude. In…
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Ultrafast electronic dynamics are typically studied using pulsed lasers. We demonstrate a complementary experimental approach: quantum simulation of ultrafast dynamics using trapped ultracold atoms. Counter-intuitively, this technique emulates some of the fastest processes in atomic physics with some of the slowest, leading to a temporal magnification factor of up to twelve orders of magnitude. In these experiments, time-varying forces on neutral atoms in the ground state of a tunable optical trap emulate the electric fields of a pulsed laser acting on bound charged particles. We demonstrate the correspondence with ultrafast science by a sequence of experiments: nonlinear spectroscopy of a many-body bound state, control of the excitation spectrum by potential shaping, observation of sub-cycle unbinding dynamics during strong few-cycle pulses, and direct measurement of carrier-envelope phase dependence of the response to an ultrafast-equivalent pulse. These results establish cold atom quantum simulation as a complementary tool for studying ultrafast dynamics.
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Submitted 26 April, 2018; v1 submitted 7 November, 2017;
originally announced November 2017.
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Quantum Emulation of Extreme Non-equilibrium Phenomena with Trapped Atoms
Authors:
Shankari V. Rajagopal,
Kurt M. Fujiwara,
Ruwan Senaratne,
Kevin Singh,
Zachary A. Geiger,
David M. Weld
Abstract:
Ultracold atomic physics experiments offer a nearly ideal context for the investigation of quantum systems far from equilibrium. We describe three related emerging directions of research into extreme non-equilibrium phenomena in atom traps: quantum emulation of ultrafast atom-light interactions, coherent phasonic spectroscopy in tunable quasicrystals, and realization of Floquet matter in strongly-…
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Ultracold atomic physics experiments offer a nearly ideal context for the investigation of quantum systems far from equilibrium. We describe three related emerging directions of research into extreme non-equilibrium phenomena in atom traps: quantum emulation of ultrafast atom-light interactions, coherent phasonic spectroscopy in tunable quasicrystals, and realization of Floquet matter in strongly-driven lattice systems. We show that all three should enable quantum emulation in parameter regimes inaccessible in solid-state experiments, facilitating a complementary approach to open problems in non-equilibrium condensed matter.
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Submitted 11 May, 2017;
originally announced May 2017.
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Effusive Atomic Oven Nozzle Design Using an Aligned Microcapillary Array
Authors:
Ruwan Senaratne,
Shankari V. Rajagopal,
Zachary A. Geiger,
Kurt M. Fujiwara,
Vyacheslav Lebedev,
David M. Weld
Abstract:
We present a simple and inexpensive design for a multichannel effusive oven nozzle which provides improved atomic beam collimation and thus extended oven lifetimes. Using this design we demonstrate an atomic lithium source suitable for trapped-atom experiments. At a nozzle temperature of 525$^{\circ}$C the collimated atomic beam flux directly after the nozzle is $1.2 \times 10^{14}$ atoms per seco…
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We present a simple and inexpensive design for a multichannel effusive oven nozzle which provides improved atomic beam collimation and thus extended oven lifetimes. Using this design we demonstrate an atomic lithium source suitable for trapped-atom experiments. At a nozzle temperature of 525$^{\circ}$C the collimated atomic beam flux directly after the nozzle is $1.2 \times 10^{14}$ atoms per second with a peak beam intensity greater than $5.0 \times 10^{16}$ atoms per second per steradian. This suggests an oven lifetime of several decades of continuous operation.
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Submitted 24 December, 2014; v1 submitted 23 July, 2014;
originally announced July 2014.
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Self-assembled Zeeman slower based on spherical permanent magnets
Authors:
V. Lebedev,
D. M. Weld
Abstract:
We present a novel type of longitudinal Zeeman slower. The magnetic field profile is generated by a 3D array of permanent spherical magnets, which are self-assembled into a stable structure. The simplicity and stability of the design make it quick to assemble and inexpensive. In addition, as with other permanent magnet slowers, no electrical current or water cooling is required. We describe the th…
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We present a novel type of longitudinal Zeeman slower. The magnetic field profile is generated by a 3D array of permanent spherical magnets, which are self-assembled into a stable structure. The simplicity and stability of the design make it quick to assemble and inexpensive. In addition, as with other permanent magnet slowers, no electrical current or water cooling is required. We describe the theory, assembly, and testing of this new design.
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Submitted 21 July, 2014;
originally announced July 2014.
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Thermometry and Refrigeration in a Two-Component Mott Insulator of Ultracold Atoms
Authors:
David M. Weld,
Hirokazu Miyake,
Patrick Medley,
David E. Pritchard,
Wolfgang Ketterle
Abstract:
Interesting spin Hamiltonians can be realized with ultracold atoms in a two-component Mott insulator (2CMI). It was recently demonstrated that the application of a magnetic field gradient to the 2CMI enables new techniques of thermometry and adiabatic cooling. Here we present a theoretical description which provides quantitative analysis of these two new techniques. We show that adiabatic reductio…
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Interesting spin Hamiltonians can be realized with ultracold atoms in a two-component Mott insulator (2CMI). It was recently demonstrated that the application of a magnetic field gradient to the 2CMI enables new techniques of thermometry and adiabatic cooling. Here we present a theoretical description which provides quantitative analysis of these two new techniques. We show that adiabatic reduction of the field gradient is capable of cooling below the Curie or Néel temperature of certain spin ordered phases.
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Submitted 1 December, 2010; v1 submitted 26 August, 2010;
originally announced August 2010.
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Spin gradient demagnetization cooling of ultracold atoms
Authors:
Patrick Medley,
David M. Weld,
Hirokazu Miyake,
David E. Pritchard,
Wolfgang Ketterle
Abstract:
A major goal of ultracold atomic physics is quantum simulation of spin Hamiltonians in optical lattices. Progress towards this goal requires the attainment of extremely low temperatures. Here we demonstrate a new cooling method which consists of applying a time-varying magnetic field gradient to a spin mixture of ultracold atoms. We have used this method to prepare isolated spin distributions at p…
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A major goal of ultracold atomic physics is quantum simulation of spin Hamiltonians in optical lattices. Progress towards this goal requires the attainment of extremely low temperatures. Here we demonstrate a new cooling method which consists of applying a time-varying magnetic field gradient to a spin mixture of ultracold atoms. We have used this method to prepare isolated spin distributions at positive and negative spin temperatures of +/-50 picokelvin. The spin system can also be used to cool other degrees of freedom, and we have used this coupling to reduce the temperature of an apparently equilibrated sample of rubidium atoms in a Mott insulating state to 350 picokelvin. These are the lowest temperatures ever measured in any system.
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Submitted 3 June, 2011; v1 submitted 23 June, 2010;
originally announced June 2010.