Abstract: A method of using an ion trap quantum computer includes performing a first measurement of bright-state population of each ion in an ion chain, the each ion coupled to one of motional modes of the ion chain, while varying laser coupling frequency, computing mode frequency of the one of the motional mode based on the measured bright-state population in the first measurement, performing a second measurement of bright-state population of each ion in the ion chain, and computing coupling strength of the each ion and the one of the motional mode by fitting the bright-state population of the each ion measured in the second measurement to a value of the bright-state population computed based on the computed mode frequency of the one of the motional modes and non-zero temperature effect of the motional modes.

Abstract: The present disclosure describes techniques for optimizing two-qubit gates performance in a quantum circuit of a quantum computing system. A quantum computing system selects, from qubits in the quantum circuit, a pair of target qubits on which to perform a quantum gate operation. The quantum computing system selects, from the plurality of qubits, a second plurality of qubits on which to introduce an intentional noise. The intentional noise is applied to the second plurality of qubits via a numerical optimizer. An optimized frequency is determined based on the applied intentional noise. The quantum gate operation is performed by modifying the pair of target qubits frequency to the optimized frequency.