Quantum Information Science, One Atom at a Time
Welcome!
The Singh Group is a new research laboratory that will be starting in the Department of Physics at The Ohio State University on Jan 1st, 2025.
The group will focus on building next-generation quantum devices and quantum information processors to explore the perplexing and extraordinary ways our universe operates, particularly at the scale of individual atoms. By developing new and innovative ways to create complex quantum systems from individually controlled single atoms, we both advance our understanding of quantum-mechanical phenomena and gain insight into how to construct transformative future devices and technologies.
The Physics Research Building (PRB) at OSU (from @osuphysics)
The laboratory will be located in the Physics Research Building at OSU (image to the left).
We are looking for motivated, collaborative, and team-oriented people at all levels (undergraduate, PhD, postdoc) to join the group! If you are excited about working together with a team to perform research at the frontier of atomic physics, quantum optics, and quantum information science, this is the lab for you! Please send a message with your motivation and CV to Kevin Singh (kevinsingh@physics.osu.edu).
Past Research
Quantum information processing with dual-species Rydberg atom arrays
Neutral atoms trapped in arrays of optical tweezers have emerged as a versatile and powerful architecture for quantum information processing, featuring programmable any-to-any qubit connectivity and high-fidelity state preparation, single-qubit operations, and two-qubit entangling gates. The diversity of approaches for constructing quantum devices based on neutral atoms offers many different complementary and compelling strategies for performing high-fidelity quantum operations, quantum error correction, and scaling to larger system sizes.
A promising methodology for building quantum processing architectures is to use multiple modalities of qubits, where one modality functions as a set of data qubits and another modality functions as a set of auxiliary qubits that can be measured in real-time to extract information about the quantum system. This information can then be used to perform in-sequence feedback operations on the data qubits to correct qubit errors in real-time or to prepare desired quantum states of the system.
At the University of Chicago, we built a dual-species Rydberg atom array of rubidium and cesium atoms, where one element can function as a set of data qubits and the other element can function as a set of auxiliary qubits. We used this platform to develop a new type of error-mitigation protocol and to establish key tools for scaling neutral-atom quantum processors, including mid-circuit readout of atom arrays, real-time processing and feed-forward, and coherent mid-circuit reloading of atomic qubits. We also demonstrated the first Rydberg blockade between different elements of the periodic table and then used this blockade to develop the first inter-element entangling gate in a neutral atom quantum processor. We combined this interspecies entanglement with the native midcircuit readout capabilities of the platform to achieve auxiliary-based quantum nondemolition measurement of a Rb qubit using an auxiliary Cs qubit. These results are important milestones for measurement-based protocols and real-time feedback control in large-scale quantum systems.
Related Publications:
S. Anand, C. E. Bradley, R. White, V. Ramesh, K. Singh, and H. Bernien. A dual-species Rydberg array. Nat. Phys. (2024)
K. Singh, C. E. Bradley, S. Anand, V. Ramesh, R. White, and H. Bernien. Mid-circuit correction of correlated phase errors using an array of spectator qubits. Science 380, 1265-1269 (2023)
K. Singh, S. Anand, A. Pocklington, J. T. Kemp, and H. Bernien. A dual-element, two- dimensional atom array with continuous mode operation. Phys. Rev. X. 12, 011040 (2022) (Featured in APS Physics Magazine)
Above: A fluorescence image of a surface-code-inspired dual-element array of Rb and Cs atoms from my work in the Bernien Lab [2]. Each blue dot is a Rb atom and each yellow dot is a Cs atom. The scale bar indicates 20 microns.
Above: Fluoresence image of individual Cs atoms dynamically arranged in 2D to form a ket symbol. [Image is from my work in the Bernien Lab @ UChicago]
Video: Rearrangement of single Rb atoms. Rb atoms are first detected with a fluorescence image and then dynamically rearranged using reconfigurable optical tweezers to form defect-free 1D chains of atoms. The spacing between the sites is approximately 3.5 microns. [Video is from my work in the Bernien Lab @ UChicago]
Non-Equilibrium Quantum Dynamics and Floquet Engineering
Neutral atoms prepared into the ground state of an energy landscape or Hamiltonian are an excellent starting point for engineering new quantum phases of matter and for exploring dynamical quantum phenomena in a controllable way. At the University of California Santa Barbara, we utilized a combination of optical lattices and a Bose-Einstein condensate of lithium atoms to explore the physics of electronic band structure in materials, with an emphasis on exploring out-of-equilibrium quantum phenomena. We observed position-space Bloch oscillations in optical lattices for the first time and used Floquet band engineering to study multi-band electronic dynamics. These studies included a demonstration of high-fidelity long-range transport, direct imaging of Floquet-Bloch bands, and the observation and characterization of prethermal steady-states when strongly driven: an important ingredient for dynamically-engineered quantum phases of matter.
Related Publications:
K. Singh, C. J. Fujiwara, Z. A. Geiger, E. Q. Simmons, M. Lipatov, A. Cao, P. Dotti, S. V. Rajagopal, R. Senaratne, T. Shimasaki, M. Heyl, A. Eckardt, and D. M. Weld. Quantifying and Controlling Prethermal Nonergodicity in Interacting Floquet Matter. Phys. Rev. X. 9, 041021 (2019)
K. M. Fujiwara, K. Singh, Z.A. Geiger, R. Senaratne, S. V. Rajagopal, M. Lipatov, and D.M. Weld. Transport in Floquet-Bloch bands. Phys. Rev. Lett. 122, 010402 (2019)
Z. Geiger, K. M. Fujiwara, K. Singh, R. Senaratne, S. V. Rajagopal, M. Lipatov, T. Shimasaki, R. Driben, V. V. Konotop, T. Meier, and D. M. Weld. Observation and Uses of Position-space Bloch Oscillations in an Ultracold Gas. Phys. Rev. Lett. 120, 213201 (2018) (Featured in APS Physics Magazine and selected for an Editor’s Viewpoint)
Left: Emergence of a Bose-Einstein condensate during optical evaporation. The sequence of experimental data shows a gas of lithium atoms undergoing a phase transition from a thermal gas into a state of matter called a Bose-Einstein condensate (BEC). Images depict optical density and are extracted from absorption imaging. The condensate has a width of approximately 100 microns and contains about half a million atoms. [Video is from my work in the Weld Lab @ UCSB]