arXiv subjects

Varun Jorapur

Publications and source records attributed to Varun Jorapur.

4 recordsLinked to original sources

arXiv2026

A low-cost modular FPGA-based control system for neutral atom tweezer arrays

We present the Quantum Atom Control Kit (QuACK), a low-cost FPGA-based control system that provides memory-efficient precise signal timing and low-delay measurement-based decision making for operating neutral atom optical tweezer array experiments. The system consists of an FPGA module connected to a host computer via USB 3.0 and multiple cable-connected modular daughterboards enabling a myriad of configurable I/O formats. In this work, digital input and output as well as analog outputs are demonstrated. Multiple experimental sequence segments can be encoded with 5 ns timing resolution. On-chip condition kernels enable fast branching between segments based on digital inputs, eliminating host intervention for time-critical decisions, while high-speed USB communication allows rapid sequence updates and host-level orchestration. We demonstrate initial system loading and rearranging neutral ytterbium-171 atoms in optical tweezers. The combination of high-resolution timing, on-chip logic, and distributed orchestration architecture makes this system well suited for atomic, molecular, and optical (AMO) experiments pursuing applications in quantum information science.

physics.atom-ph↗

arXiv2026

InterQnet: A Heterogeneous Full-Stack Approach to Co-designing Scalable Quantum Networks

Quantum communications have progressed significantly, moving from a theoretical concept to small-scale experiments to recent metropolitan-scale demonstrations. As the technology matures, it is expected to revolutionize quantum computing in much the same way that classical networks revolutionized classical computing. Quantum communications will also enable breakthroughs in quantum sensing, metrology, and other areas. However, scalability has emerged as a major challenge, particularly in terms of the number and heterogeneity of nodes, the distances between nodes, the diversity of applications, and the scale of user demand. This paper describes InterQnet, a multidisciplinary project that advances scalable quantum communications through a comprehensive approach that improves devices, error handling, and network architecture. InterQnet has a two-pronged strategy to address scalability challenges: InterQnet-Achieve focuses on practical realizations of heterogeneous quantum networks by building and then integrating first-generation quantum repeaters with error mitigation schemes and centralized automated network control systems. The resulting system will enable quantum communications between two heterogeneous quantum platforms through a third type of platform operating as a repeater node. InterQnet-Scale focuses on a systems study of architectural choices for scalable quantum networks by developing forward-looking models of quantum network devices, advanced error correction schemes, and entanglement protocols. Here we report our current progress toward achieving our scalability goals.

quant-ph↗

arXiv2023

High density loading and collisional loss of laser cooled molecules in an optical trap

We report optical trapping of laser-cooled molecules at sufficient density to observe molecule-molecule collisions for the first time in a bulk gas. SrF molecules from a red-detuned magneto-optical trap (MOT) are compressed and cooled in a blue-detuned MOT. Roughly 30% of these molecules are loaded into an optical dipole trap with peak number density $n_0 \approx 3\times 10^{10} \text{ cm}^{-3}$ and temperature $T\approx40$ $μ$K. We observe two-body loss with rate coefficient $β= 2.7^{+1.2}_{-0.8}\times 10^{-10} \text{ cm}^3 \text{ s}^{-1}$. Achieving this density and temperature opens a path to evaporative cooling towards quantum degeneracy of laser-cooled molecules.

physics.atom-ph↗

arXiv2021

Polarization Enhanced Deep Optical Dipole Trapping of $Λ$-cooled Polar Molecules

We demonstrate loading of SrF molecules into an optical dipole trap (ODT) via in-trap $Λ$-cooling. We find that this cooling can be optimized by a proper choice of relative ODT and $Λ$ beam polarizations. In this optimized configuration, we observe molecules with temperatures as low as 14(1) $μ$K in traps with depths up to 570 $μ$K. With optimized parameters, we transfer $\!\sim\!5$% of molecules from our radio-frequency magneto-optical trap into the ODT, at a density of $\sim\!2\times 10^{9}$ cm$^{-3}$, a phase space density of $\sim\!2\times 10^{-7}$, and with a trap lifetime of $\!\sim\!1$ s.

physics.atom-ph↗