The Sycamore gate is a two-qubit gate equivalent to FSimGate(π/2, π/6).
cirq_google.ops.SYC( *qubits, **kwargs )
The unitary of this gate is
[[1, 0, 0, 0], [0, 0, -1j, 0], [0, -1j, 0, 0], [0, 0, 0, exp(- 1j * π/6)]]
This gate can be performed on the Google's Sycamore chip and is close to the gates that were used to demonstrate quantum supremacy used in this paper: https://www.nature.com/articles/s41586-019-1666-5