Final Report Summary - QUOMP (Quantum optics with microwave photons building a tool-box based on superconducting technology)
In the ERC-project QUOMP (Quantum optics with microwave photons) we have worked with superconducting circuits that contain SQUIDs (Superconducting Quantum Interference Devices). These SQUIDS are incorporated both in microwave resonators and so called quantum bits (qubits, the basic building blocks for quantum computers). These devices operate at the microwave frequencies, and their frequencies can be tuned by applying magnetic flux to the SQUID. We study how microwave photons interact with the superconducting qubits which act as artificial atoms, thus doing quantum optics on-chip. The cavities can be used to store microwave photons and enhance the interaction with the qubits/atoms.
Tuning the flux through the SQUID very fast, we can change the boundary condition for the electromagnetic field in a resonator or in a transmission line. This mimics a mirror moving at very high velocities, in fact close to the speed of light. In this way, we can combine quantum physics with relativistic physics.
More recently we have also worked with surface acoustic waves to study the quantum properties of sound and its interaction with the artificial atoms.
We have been able to reach several scientifically and technologically important results. Most results are basic research and have mainly a scientific value, but in the longer run they may be important for quantum information. We have achieved the following goals:
- The first demonstration of the dynamical Casimir effect, where photons are generated out of the vacuum due to the relativistic boundary condition that the electromagnetic field is exposed to.
- We have demonstrated a fast and efficient single-photon router in the microwave regime, where individual photons can be routed to one of two output ports on-chip.
- A Q-tunable superconducting resonator has been operated to store and release photons. The storage time was upto 17µs and the release time was 14 ns. This allows us to store microwave photons in the resonator and the let them out on demand.
- Quantum limited parametric amplification in a multimode cavity. We have made a tunable superconducting resonator which can be pumped parametrically using a SQUID. We have demonstrated new modes of operation using several modes, and we find that device is quantum limited,i.e it does not any more noise than what is required by quantum mechanics.
- Combining surface acoustic waves with our artificial atoms we have been able to demonstrate interaction between a qubit and sound. The atom is engineered to couple stronger to sound than to light. We can excite the atom and then listen to the sound it emits when relaxing, and we can observe nonlinear reflection of the sound on the atom.
Tuning the flux through the SQUID very fast, we can change the boundary condition for the electromagnetic field in a resonator or in a transmission line. This mimics a mirror moving at very high velocities, in fact close to the speed of light. In this way, we can combine quantum physics with relativistic physics.
More recently we have also worked with surface acoustic waves to study the quantum properties of sound and its interaction with the artificial atoms.
We have been able to reach several scientifically and technologically important results. Most results are basic research and have mainly a scientific value, but in the longer run they may be important for quantum information. We have achieved the following goals:
- The first demonstration of the dynamical Casimir effect, where photons are generated out of the vacuum due to the relativistic boundary condition that the electromagnetic field is exposed to.
- We have demonstrated a fast and efficient single-photon router in the microwave regime, where individual photons can be routed to one of two output ports on-chip.
- A Q-tunable superconducting resonator has been operated to store and release photons. The storage time was upto 17µs and the release time was 14 ns. This allows us to store microwave photons in the resonator and the let them out on demand.
- Quantum limited parametric amplification in a multimode cavity. We have made a tunable superconducting resonator which can be pumped parametrically using a SQUID. We have demonstrated new modes of operation using several modes, and we find that device is quantum limited,i.e it does not any more noise than what is required by quantum mechanics.
- Combining surface acoustic waves with our artificial atoms we have been able to demonstrate interaction between a qubit and sound. The atom is engineered to couple stronger to sound than to light. We can excite the atom and then listen to the sound it emits when relaxing, and we can observe nonlinear reflection of the sound on the atom.