In superconducting quantum computing one typically uses Josephson junctions (superconducting tunnel junctions) to make anharmonic resonators that act as qubits.
Junctions are made by litography like classical CPUs. Such qubits are prepared by microwave pulses that correspond to rotations on the Bloch sphere.
Entanglement between qubits is generated by variable coupling (in the simplest case adjusting current through a Josephson junction changes its inductance and thus coupling). The Junctions are almost purely reactive so no loss is associated with them.
Readout is usually done by reflecting a microwave pulse from a coupled microwave resonator and then determining the phase of the reflected pulse (which depends on the state of the qubit).
