High fidelity qubit readout at Heisenberg limit
We aim to improve the readout fidelity of qubits by using squeezed light. In squeezed states, the noise of the electromagnetic field in one quadrature is reduced below the level of vacuum quantum fluctuations. While this effect is widely exploited in the optical domain, generating and observing squeezing at microwave frequencies is significantly more challenging.
One proposed strategy has been to use squeezing to enhance the effective coupling between a resonator and a qubit. However, this comes with a drawback: squeezing can also increase qubit decay through photon loss, which can limit its usefulness for improving readout.
We are therefore exploring an alternative approach based on two-mode squeezed light. This technique creates pairs of entangled photons distributed across two electromagnetic modes. By exploiting the correlations between these modes, it becomes possible to extract information about the qubit state with improved precision beyond standard shot-noise limits.
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