Berlin 2024 – scientific programme
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O: Fachverband Oberflächenphysik
O 21: Focus Session: Spins on Surfaces studied by Atomic Scale Spectroscopies III
O 21.6: Talk
Tuesday, March 19, 2024, 12:00–12:15, MA 004
Pulse scheme to create and detect entanglement in surface spin systems using a tunneling microscope — •Rik Broekhoven1, Curie Lee2,3, Soo-hyon Phark2,4, Sander Otte1, and Christoph Wolf2,4 — 1Department of Quantum Nanoscience, Kavli Institute of Nanoscience, Delft University of Technology, 2628 CJ Delft, the Netherlands — 2Center for Quantum Nanoscience, Institute for Basic Science (IBS), Seoul 03760, Korea — 3Department of Physics, Ewha Womans University, Seoul 03760, Korea — 4Ewha Womans University, Seoul 03760, Korea
Being able to certify quantum entanglement is an essential element of quantum-coherent applications which has not yet been shown in spins on a surface. Here, we present a way to unambiguously identify entanglement by exploiting that entangled states undergo a free evolution with a characteristic time constant different from any other evolution in the system. Our approach is compatible with multi-spin resonance control in a scanning tunneling microscope (STM). We suggest a pulse scheme that first creates an entangled spin pair outside of the STM junction and subsequently projects the accumulated phase during free evolution on the population of one of the spins, which in turn can be read out through a weakly coupled sensor spin. The resulting measurement signal is an oscillation in the STM current at a time scale proportional to the spin pair exchange coupling if and only if the pair was entangled. We show that this scheme can be implemented using realistic simulation parameters and study the expected measurement contrast as a function of temperature and decoherence times.
Keywords: coherence; electron spin resonance; entanglement; scanning tunneling microscope; quantum information