88Sr+ ion trap apparatus for generating 408 nm photons

Review of Scientific Instruments · 2026-01-01

We describe a 88Sr+ ion trap apparatus with the capability to produce high-quality 408 nm photons aimed at distributed quantum computing and networking applications. This instrument confines ion chains using a surface electrode trap with a two-dimensional magneto-optical trap as an atomic source. Several laser systems spanning 400-1100 nm are used to achieve high-fidelity state preparation and readout. Photons are produced via the decay of an exited state, which is accessed using a custom 408 nm laser system that produces 150 ps optical pulses using non-linear photonics. We demonstrate single-photon production through a Hanbury Brown-Twiss measurement for one to six ions.

Collective magnetism of atomic momentum states

ArXiv.org · 2025-02-13 · 2 citations

Organization and ordering from interactions in many-body systems underlies our understanding of phases of classical and quantum matter. Magnetism has played a particularly foundational role in the study of many-body phases. Here, we explore the collective magnetism that emerges from two laser-coupled momentum modes of a scalar bosonic quantum gas. We employ adiabatic state preparation and explore the collective magnetization response to an applied bias potential, finding that the relative increase of interactions leads to an enhanced and muted response for the ground state and excited state, respectively. We further find evidence for significant $Z_2$ symmetry breaking of the sample magnetization for the ground state, consistent with the expected beyond-mean-field behavior. These results suggest that the nonlinear interactions of scalar Bose condensates could provide a simple, direct path towards the squeezing of momentum states for quantum sensing.

88Sr+ ion trap apparatus for generating 408 nm photons

ArXiv.org · 2025-07-02

We describe a 88Sr+ ion trap apparatus with the capability to produce high-quality 408 nm photons aimed at distributed quantum computing and networking applications. This instrument confines ion chains using a surface electrode trap with a two-dimensional magneto-optical trap as an atomic source. Several laser systems spanning 400-1100 nm are used to achieve high fidelity state preparation and readout. Photons are produced via the decay of an exited state, which is accessed using a custom 408 nm laser system that produces 150 ps optical pulses using non-linear photonics. We demonstrate single photon production through a Hanbury Brown-Twiss measurement for one to six ions.

Rotational magic conditions for ultracold molecules in the presence of Raman and Rayleigh scattering

New Journal of Physics · 2024-06-01 · 1 citations

Abstract Molecules have vibrational, rotational, spin-orbit and hyperfine degrees of freedom or quantum states, each of which responds in a unique fashion to external electromagnetic radiation. The control over superpositions of these quantum states is key to coherent manipulation of molecules. For example, the better the coherence time the longer quantum simulations can last. The important quantity for controlling an ultracold molecule with laser light is its complex-valued molecular dynamic polarizability. Its real part determines the tweezer or trapping potential as felt by the molecule, while its imaginary part limits the coherence time. Here, our study shows that efficient trapping of a molecule in its vibrational ground state can be achieved by selecting a laser frequency with a detuning on the order of tens of GHz relative to an electric-dipole-forbidden molecular transition. Close proximity to this nearly forbidden transition allows to create a sufficiently deep trapping potential for multiple rotational states without sacrificing coherence times among these states from Raman and Rayleigh scattering. In fact, we demonstrate that magic trapping conditions for multiple rotational states of the ultracold 23 Na 87 Rb polar molecule can be created.

Interacting Stark localization dynamics in a three-dimensional lattice Bose gas

Physical review. A/Physical review, A · 2023-04-28 · 2 citations

We measure the thermalization dynamics of a lattice Bose gas that is Stark localized by a parabolic potential. A nonequilibrium thermal density distribution is created by quickly removing an optical barrier. The resulting spatiotemporal dynamics are resolved using Mardia's $B$ statistic, which is a measure sensitive to the shape of the entire density distribution. We conclude that equilibrium is achieved for all lattice potential depths that we sample, including the strongly interacting and localized regime. However, thermalization is slow and nonexponential, requiring up to 500 tunneling times. We show that the Hubbard $U$ term is not responsible for thermalization via comparison to an exact diagonalization calculation, and we rule out equilibration driven by lattice-light heating by varying the laser wavelength. The thermalization timescale is comparable to the next-nearest-neighbor tunneling time, which suggests that a continuum, strongly interacting theory may be needed to understand equilibration in this system.

Rotational magic conditions for ultracold molecules in the presence of Raman and Rayleigh scattering

arXiv (Cornell University) · 2023-10-24

Molecules have vibrational, rotational, spin-orbit and hyperfine degrees of freedom or quantum states, each of which responds in a unique fashion to external electromagnetic radiation. The control over superpositions of these quantum states is key to coherent manipulation of molecules. For example, the better the coherence time the longer quantum simulations can last. The important quantity for controlling an ultracold molecule with laser light is its complex-valued molecular dynamic polarizability. Its real part determines the tweezer or trapping potential as felt by the molecule, while its imaginary part limits the coherence time. Here, our study shows that efficient trapping of a molecule in its vibrational ground state can be achieved by selecting a laser frequency with a detuning on the order of tens of GHz relative to an electric-dipole-forbidden molecular transition. Close proximity to this nearly forbidden transition allows to create a sufficiently deep trapping potential for multiple rotational states without sacrificing coherence times among these states from Raman and Rayleigh scattering. In fact, we demonstrate that magic trapping conditions for multiple rotational states of the ultracold $^{23}$Na$^{87}$Rb polar molecule can be created.

Entangleware Sequencer: A Control Platform for Atomic Physics Experiments

arXiv (Cornell University) · 2023-11-15

Experimental quantum physics and computing platforms rely on sophisticated computer control and timing systems that must be deterministic. An exemplar is the sequence used to create a Bose-Einstein condensate at the University of Illinois, which involves 46,812 analog and digital transitions over 100 seconds with 20 ns timing precision and nanosecond timing drift. We present a control and sequencing platform, using industry-standard National Instruments hardware to generate the necessary digital and analog signals, that achieves this level of performance. The system uses a master 10 MHz reference clock that is conditioned to the Global Positioning Satellite constellation and leverages low-phase-noise clock distribution hardware for timing stability. A Python-based user front-end provides a flexible language to describe experimental procedures and easy-to-implement version control. A library of useful peripheral hardware that can be purchased as low-cost evaluation boards provides enhanced capabilities. We provide a GitHub repository containing example python sequences and libraries for peripheral devices as a resource for the community.

Active Cancellation of Servo-Induced Noise on Stabilized Lasers via Feedforward

Physical Review Applied · 2022-12-02 · 28 citations

Many precision laser applications require active frequency stabilization. However, such stabilization loops operate by pushing noise to frequencies outside their bandwidth, leading to large ``servo bumps'' that can have deleterious effects for certain applications. The prevailing approach to filtering this noise is to pass the laser through a high-finesse optical cavity, which places constraints on the system design. Here, we propose and demonstrate a different approach where a frequency error signal is derived from a beat note between the laser and the light that passes through the reference cavity. The phase noise derived from this beat note is fed forward to an electro-optic modulator after the laser, carefully accounting for relative delay, for real-time frequency correction. With a hertz-line-width laser, we show $\ensuremath{\gtrsim}20\phantom{\rule{0.2em}{0ex}}\mathrm{dB}$ noise suppression at the peak of the servo bump (approximately $250\phantom{\rule{0.2em}{0ex}}\mathrm{kHz}$) and a noise-suppression bandwidth of approximately $5\phantom{\rule{0.2em}{0ex}}\mathrm{MHz}$---well beyond the servo bump. By simulating the Rabi dynamics of a two-level atom with our measured data, we demonstrate substantial improvements to the pulse fidelity over a wide range of Rabi frequencies. Our approach offers a simple and versatile method for obtaining a clean spectrum of a narrow-line-width laser, as required in many emerging applications of cold atoms, and is readily compatible with commercial systems that may even include wavelength conversion.

Accelerating Progress Towards Practical Quantum Advantage: The Quantum Technology Demonstration Project Roadmap

arXiv (Cornell University) · 2022-10-26 · 3 citations

Quantum information science and technology (QIST) is a critical and emerging technology with the potential for enormous world impact and is currently invested in by over 40 nations. To bring these large-scale investments to fruition and bridge the lower technology readiness levels (TRLs) of fundamental research at universities to the high TRLs necessary to realize the promise of practical quantum advantage accessible to industry and the public, we present a roadmap for Quantum Technology Demonstration Projects (QTDPs). Such QTDPs, focused on intermediate TRLs, are large-scale public-private partnerships with a high probability of translation from laboratory to practice. They create technology demonstrating a clear 'quantum advantage' for science breakthroughs that are user-motivated and will provide access to a broad and diverse community of scientific users. Successful implementation of a program of QTDPs will have large positive economic impacts.

Interacting Stark localization dynamics in a three-dimensional lattice Bose gas

arXiv (Cornell University) · 2022-11-22 · 1 citations

We measure the thermalization dynamics of a lattice Bose gas that is Stark localized by a parabolic potential. A non-equilibrium thermal density distribution is created by quickly removing an optical barrier. The resulting spatio-temporal dynamics are resolved using Mardia's $B$ statistic, which is a measure sensitive to the shape of the entire density distribution. We conclude that equilibrium is achieved for all lattice potential depths that we sample, including the strongly interacting and localized regime. However, thermalization is slow and non-exponential, requiring up to 500 tunneling times. We show that the Hubbard $U$ term is not responsible for thermalization via comparison to an exact diagonalization calculation, and we rule out equilibration driven by lattice-light heating by varying the laser wavelength. The thermalization timescale is comparable to the next-nearest-neighbor tunneling time, which suggests that a continuum, strongly interacting theory may be needed to understand equlibration in this system.