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HL: Fachverband Halbleiterphysik
HL 11: Materials and Devices for Quantum Technology I (joint session HL/QI)
HL 11.6: Talk
Monday, March 18, 2024, 16:15–16:30, EW 203
Protocols to measure the non-Abelian Berry phase by pumping a spin qubit through a quantum-dot loop — •Baksa Kolok1 and Andras Palyi1,2 — 1Department of Theoretical Physics, Institute of Physics, Budapest University of Technology and Economics, Muegyetem rkp. 3., H-1111 Budapest, Hungary — 2MTA-BME Quantum Dynamics and Correlations Research Group, Muegyetem rkp. 3., H-1111 Budapest, Hungary
A quantum system constrained to a degenerate energy eigenspace can undergo a nontrival time evolution upon adiabatic driving, described by a non-Abelian Berry phase. This type of dynamics may provide logical gates in quantum computing that are robust against timing errors. A strong candidate to realize such holonomic quantum gates is an electron or hole spin qubit trapped in a spin-orbit-coupled semiconductor, whose twofold Kramers degeneracy is protected by time-reversal symmetry. Here, we propose and quantitatively analyze protocols to measure the non-Abelian Berry phase by pumping a spin qubit through a loop of quantum dots. One of these protocols allows to characterize the local internal Zeeman field directions in the dots of the loop. We expect a nearterm realisation of these protocols, as all key elements have been already demonstrated in spin-qubit experiments. These experiments would be important to assess the potential of holonomic quantum gates for spin-based quantum information processing.
Keywords: geometrical phase; holonomic quantum computing; spin-orbit interaction; spin qubits; quantum dot arrays