Simultaneous parity-dependent XY entangling gates in superconducting qubit chains

Multi-qubit operations have the potential to efficiently generate many-body entanglement. In this work, we investigate the simultaneous coupling of a chain of superconducting qubits. Starting from the well-known full transfer of a single excitation along a chain of XY coupled qubits, we review parameter settings that allow for partial excitation transfer and extend it to multiple excitations. We find that every pair of qubits on opposite sides with respect to the center undergoes the same XY rotation with the angle determined by a set of coupling and detuning parameters. Moreover, by applying Z-gates, we find that the sign of the rotation angle depends on the parity of the qubits in between. This multi-qubit operation directly implements a parametrizable Trotter step for Jordan-Wigner Fermions with potential application in Fermi simulations, VQE, parity measurement of long qubit chains, and the efficient generation of multi-qubit gates.