Magnet-less circulator for hybrid-classical qubit read-out systems with built-in phase modulation

A method, comprising:

• routing, by a system comprising at least one processor, a qubit signal flow obtained at a first circulator port of a magnet-less circulator device to a second circulator port of the magnet-less circulator device, in conjunction with impeding the qubit signal flow from the first circulator port to a third circulator port of the magnet-less circulator device, comprising:
• outputting, via the system, a modulated control signal to:
• a first radio frequency-superconducting quantum interference device (rf-SQUID) set inductively coupled to a first tank circuit, to resonate, based on a first phase, the first tank circuit at a first frequency,
• a second rf-SQUID set inductively coupled to a second tank circuit, to resonate, based on a second phase that is different from the first phase, the second tank circuit at a second frequency that is different from the first frequency, and
• a third rf-SQUID set inductively coupled to the third tank circuit, to resonate, based on a third phase that is different from the first phase, and different from the second phase, the third tank circuit at a third frequency that is different from the first frequency and the second frequency,
• wherein respective resonations of the first tank circuit at the first frequency, of the second tank circuit at the second frequency, and the third tank circuit at the third frequency result in an electronic angular momentum being imparted to the magnet-less circulator device, and wherein the electronic angular momentum being imparted to the magnet-less circulator device results in constructive interference of the first frequency and the second frequency that routes the qubit signal flow from the first circulator port to the second circulator port, and further results in destructive interference of the first frequency and the third frequency that impedes the qubit signal flow from the first circulator port to the third circulator port.

A system, comprising:

• a first magnet-less circulator device, comprising:
• a first circulator port, a second circulator port, and a third circulator port, wherein the first circulator port is coupled to a qubit signal;
• a first inductor-capacitor (LC) tank circuit electrically coupled to the first circulator port, and inductively coupled to a first radio frequency-superconducting quantum interference device (rf-SQUID) set,
• a second LC tank circuit electrically coupled to the second circulator port, and inductively coupled to a second rf-SQUID set, and
• a third LC tank circuit electrically coupled to the third circulator port, and inductively coupled to a third rf-SQUID set;
• a second magnet-less circulator device, comprising:
• a fourth circulator port, a fifth circulator port, and a sixth circulator port, wherein the fourth circulator port is coupled to the second circulator port of the first magnet-less circulator device;
• a fourth LC tank circuit electrically coupled to the fourth circulator port and inductively coupled to a fourth rf-SQUID set;
• a fifth LC tank circuit electrically coupled to the fifth circulator port and inductively coupled to a fifth rf-SQUID set;
• and
• a sixth LC tank circuit electrically coupled to the sixth circulator port and inductively coupled to a sixth rf-SQUID set;
• and
• a computing device that outputs a modulated control signal to the first rf-SQUID set corresponding to a first phase shift, the second rf-SQUID set corresponding to a second phase shift, the third rf-SQUID set corresponding to a third phase shift, the fourth rf-SQUID set corresponding to a fourth phase shift, the fifth rf-SQUID set corresponding to a fifth phase shift, and the sixth rf-SQUID set corresponding to a sixth phase shift, to respectively resonate:
• the first LC tank circuit at a first frequency,
• the second LC tank circuit at a second frequency that is different from the first frequency,
• the third LC tank circuit at a third frequency that is different from the first frequency and different from the second frequency;
• the fourth LC tank circuit at a fourth frequency,
• the fifth LC tank circuit at a fifth frequency that is different from the fourth frequency, and
• the sixth LC tank circuit at a sixth frequency that is different from the fourth frequency and different from the fifth frequency;
• wherein the first frequency, the second frequency and the third frequency impart a first electronic angular momentum to the first magnet-less circulator device, that results in first constructive interference of the first frequency and the second frequency, and first destructive interference of the first frequency and the third frequency, that routes, in a clockwise direction, the qubit signal flow from the first circulator port to the second circulator port, and impedes the qubit signal flow from the first circulator port to the third circulator;
• and
• wherein the fourth frequency, the fifth frequency and the sixth frequency impart a second electronic angular momentum to the second magnet-less circulator device, that results in a second constructive interference of the fourth frequency and the sixth frequency that routes, in a counterclockwise direction, the qubit signal flow from the fourth circulator port, as obtained from the second circulator port to the sixth circulator port, and that results in a second destructive interference of the fourth frequency and the fifth frequency that impedes the qubit signal flow from the fourth circulator port to the fifth circulator port.