Joint CPM/INTRIQ Seminar

Modulating qubit spectra to optimize photon-mediated operations in QIST (quantum information science and technologies)

Herbert Fotso

Department of Physics
University at Buffalo

Photon-mediated operations are essential for a variety of quantum information processing operations. For optimal performance, stringent constraints should be satisfied by relevant quantum systems. For instance, for the typical implementation of the Hong-Ou-Mandel two-photon interference between distant quantum nodes, spatial and temporal profiles of the emitted photons are required to be identical. On the one hand, such conditions are not a priori satisfied between systems that may separately be the most suited for different quantum operations. On the other hand, leveraging advantageous capacities of different systems is key to the currently envisioned heterogeneous quantum platforms. Besides, even for nominally identical systems, the operating frequencies might differ by many linewidths as a result of spectral diffusion. To overcome such spectral disparities, spectral modulation with external control fields has garnered a great deal of attention in recent years [1-3]. In this talk, we will discuss how such spectral modulation with external fields might play an important role in scalable quantum platforms. For example, we have found that emitters with emission frequencies that differ by many linewidths may be made indistinguishable by experimentally achievable pulse sequences[2].

[1] Herbert F. Fotso, A. E. Feiguin, D. D. Awschalom, and V. V. Dobrovitski, Suppressing Spectral Diffusion of Emitted Photons with Optical Pulses, Phys. Rev. Lett. 116, 033603 (2016).
[2] Herbert F. Fotso, Pulse-Enhanced Two-Photon Interference with Solid State Quantum Emitters, Phys. Rev. B, 100, 094309 (2019).
[3] Herbert F. Fotso, Tuning Spectral Properties of Individual and Multiple Quantum Emitters in Noisy Environments, Phys. Rev. A 107, 023719 (2023).