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Caltech

Quantum Matter Seminar

Monday, February 26, 2024
4:00pm to 5:00pm
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East Bridge 114
Quantum processors and quantum networks atom-by-atom
Hannes Bernien, Professor, University of Chicago,

Reconfigurable arrays of neutral atoms are an exciting platform to study quantum many-body phenomena and quantum information protocols. Their excellent coherence combined with programmable Rydberg interactions have led to intriguing observations such as quantum phase transitions, the discovery of quantum many-body scars, and novel quantum computing architectures.

Here, I will introduce new methods for controlling and measuring atom arrays that open up compelling directions in quantum state control, quantum feedback and many-body physics. First, I will introduce a dual-species atomic array in which the second atomic species can be used to measure and control the primary species. We use an array of cesium qubits to correct correlated phase errors on an array of rubidium data qubits [1]. Rydberg interactions between the two species lead to novel regimes, including greatly enhanced resonant dipole interactions, that we use to demonstrate a 2-qubit gate and quantum non-demolition readout [2].

An alternative, hybrid approach for engineering interactions and scaling these quantum systems is the coupling of atoms to nanophotonic structures in which photons mediate interactions between atoms. Such a system can function as the building block of a large-scale quantum network. In this context, I will present quantum network node architectures that are capable of long-distance entanglement distribution at telecom wavelengths [3] and show how to combine atom-array capabilities with large photonic chips [4].

[1] Singh, Bradley, Anand, Ramesh, White, Bernien, Science 380, 1265 (2023)

[2] Anand, Bradley, White, Ramesh, Singh, Bernien, arXiv:2401.10325 (2024)

[3] Menon, Singh, Borregaard, Bernien NJP 22, 073033 (2020)

[4] Menon, Glachman, Pompili, Dibos, Bernien, arXiv:2311.02153 (2023)