B O S C H U N D S I E M E N S H A U S G E R Ä T E G R U P P E Utilizing error correction for quantum sensing Yuval Vinkler Hebrew University of Jerusalem Work done with: Alex Retzker Gilad Arrad Dorit Aharonov Talk at the Israel Physical Society Conference

Quantum Sensing Quantum sensing scales as: One method to improve coherence time: dynamical decoupling. In Quantum sensing a signal is measured by reading its effects on a system. For example: for a signal g along the z direction Can this be done with error correction?

General Idea of error correction for quantum computing Code error1 error2 Error N Logical operation

General Idea of error correction for quantum sensing Code error1 error2 Error N Sensing signal However, the sensing signal is weak/slow and the logical operation is strong/fast

Advantage – use of protected qubits Code Sensing qubit Good qubits

Magnetic noise The code using a good qubit: noise signal The effect of noise: Signal: While dynamical decoupling must operate faster than the correlation time of the noise, error correction must work faster than the magnitude of the noise, regardless its power spectrum.

Magnetic Noise – Numerical Simulation Works even with strong noise (with respect to g). Strong dependence on the frequency of operations – the faster we act, the better the signal.

Summary The principles of Error Corrections were employed to improve quantum sensing. For noise perpendicular to the sensing signal – a significant improvement in coherence time. Operations must be faster than noise strength. Can be slower noise power spectrum. Outlook: experiments (in progress), decoherence type spectroscopy. The principles of Error Corrections were employed to improve quantum sensing. For noise perpendicular to the sensing signal – a significant improvement in coherence time. Operations must be faster than noise strength. Can be slower noise power spectrum. Outlook: experiments (in progress), decoherence type spectroscopy.