Arrays of neutral atoms trapped in optical tweezers are a fast-rising platform for quantum simulation, quantum computation, and quantum metrology. They offer exquisite control over many degrees of freedom, including the internal quantum states, motional states, array geometries, and doping. By driving the atoms to highly excited Rydberg states, the atoms can be made to interact over long range. The interacting atoms can in turn be exploited for many applications like simulating quantum magnetism and executing quantum logic gates.
Our laboratory focuses on using scalable and programmable atom arrays as quantum information processors, quantum simulators, and quantum sensors.
Quantum simulation
Advanced materials like superconductors have the potential to change energy transport as we know it. However, their dynamics on the microscopic scale remain poorly understood as they are difficult to simulate with classical computers. A promising solution is to assemble ultracold atoms as quantum building blocks to mimic these advanced materials and directly observe the dynamics in these clean systems.
Our lab has recently found new ways to explore rich dynamics by engineering fractures in the Hilbert space of a quantum many-body system, such that the Hilbert space shatters into exponentially many disjointed subspaces. This opens up possibilities, for instance, to observe quantum thermalization in a way that runs counter to our conventional understanding and may be applied to control entanglement dynamics in quantum processors and quantum sensors.
Programmable atom arrays
Floquet-tailored Rydberg interactions
Quantum processors generally benefit from increased qubit connectivity, improved coherence, and new state-initialization pathways. We show that neutral atom quantum processors can be advanced on all three critical fronts through a simple, robust approach – Floquet frequency modulation:
- We demonstrate Rydberg-blockade entanglement beyond the conventional blockade radius for two tweezer-trapped atoms and showed how the enlarged entanglement range improves qubit connectivity in a neutral atom array.
- We find that the coherence of entangled states can be protected against Doppler dephasing, which is the dominant mechanism limiting entangled-state coherence in atom arrays.
- We propose a robust method to realize Rydberg anti-blockade states in the steady state for two closely-spaced atoms, which cannot be otherwise achieved with a conventional static drive.
Nat. Commun. publication, CQT highlight
Scaling up atom arrays
Efficient defect-free atom array assembly
We realize large pristine arrays containing hundreds of atoms with high success rates by using a new algorithm that moves multiple atoms at the same time. Defect-free arrays of atoms are an important platform for quantum simulation and quantum computing, and large arrays allow us to harness more atoms for increased simulation and computing power. However, producing large defect-free arrays can be challenging because of the losses encountered during assembly. One way to beat the losses is to build the arrays as quickly as possible. Our new algorithm achieves a significant speedup over existing algorithms by using multiple tweezers to sort atoms in parallel. We have also used our new algorithm to create a range of pristine patterns including a honeycomb and a lion head.
Phys. Rev. Applied publication, APS Physics highlight, NUS news highlight, Phys.org, CQT highlight
Magic wavelength tweezers
We use a new class of magic wavelengths (for the D1 transition in alkalis) to achieve an order-of-magnitude reduction in the optical power required per tweezer trap, which allows us to scale up the atom array size correspondingly.
Phys. Rev. Research publication, CQT highlight