Zhao Zhang

Recoil-free Quantum Gates with Optical Qubits

Zhao Zhang [1,2,3], Léo Van Damme, Marco Rossignolo [4], Lorenzo Festa [1,2], Max Melchner [1,5,2], Robin Eberhard [1,5,2], Dimitrios Tsevas [1,5,2], Kevin Mours [1,5,2], Eran Reches [1,5,2], Johannes Zeiher [1,5,2], Sebastian Blatt [1,5,2], Immanuel Bloch [1,5,2], Steffen J. Glaser [3,2], Andrea Alberti [1,5,2]

Abstract

We propose a scheme to perform optical pulses that suppress the effect of photon recoil by three orders of magnitude compared to ordinary pulses in the Lamb-Dicke regime. We derive analytical insight about the fundamental limits to the fidelity of optical qubits for trapped atoms and ions. This paves the way towards applications in quantum computing for realizing $>1000$ of gates with an overall fidelity above 99\%.

Enhanced micromotion compensation using a phase modulated light field

K. J. Arnold [1], N. Jayjong [1], M. L. D. Kang [1], Qin Qichen [1], Zhao Zhang [1], Qi Zhao [1], M. D. Barrett [2]

Abstract

We investigate sideband spectroscopy of a trapped ion using a probe laser phase modulated at the trap drive frequency. The enhanced sensitivity of our technique over traditional sideband spectroscopy allows us to detect stray fields of $0.01\,\mathrm{V/m}$ on a timescale of a few minutes and detect differential phases of $5\,μ\mathrm{rad}$ between applied ac potentials. We also demonstrate the ability suppress Doppler shifts from excess motion to well below the limit imposed by the intrinsic motion of the ion in the vibrational ground-state. The technique we introduce can be readily implemented in any ion trap system that utilizes sideband spectroscopy for micromotion compensation and can be seamlessly integrated into experiments in a fully automated way