Cirq has two in-built realizations of quantum hardware, which are realized as GridQubit() and LineQubit() classes (naming convention is slightly disturbing:).
GridQubit device mimics connectivity of Google's quantum chips (Bristlecone, Sycamore) and qubits are arranged in a 2D grid with nearest-neighbor couplings. https://github.com/quantumlib/Cirq/blob/master/cirq/devices/grid_qubit.py
LineQubit device represents chips with 1D geometry, where qubits are arranged in a line and again only nearest-neighbor qubits are coupled.
Is there any possibility to specify a custom hardware coupling map? E.g. to specify adjacency matrix of new connectivity graph?
It seems that a user has to create his/her own device class for such functionality.