Dispersive readout of qubit states: towards realizing spin qubits using electrons on helium

Electrons on the surface of liquid helium present an extremely clean two-dimensional electron system. Thanks to its cleanness, the quantum states of the electrons on helium are expected to have a long relaxation time, which provides a perfect platform to realize qubits with [1]. In particular, spin states are expected to have an extremely long relaxation time: T2~100s [2].
Recently, we propose and experimentally demonstrate a new readout technique for the hydrogen-like quantized states (Rydberg states) of many electrons on helium [3]. This new technique was inspired by the dispersive readout technique used in semiconductor quantum dots [4] and in Penning traps [5]. Currently, we are working on the measurement of the relaxation time of the Rydberg state of the electrons on helium using this technique. We also show that this technique can potentially be used to detect spin states of a single electron by introducing an interaction between the Rydberg states and the spin states.
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