A5049856296- Quantum Information and Cryptography
- Quantum and electron transport phenomena
- Mechanical and Optical Resonators
- Cold Atom Physics and Bose-Einstein Condensates
- Quantum Mechanics and Applications
- Physics of Superconductivity and Magnetism
- Quantum Electrodynamics and Casimir Effect
- Semiconductor Quantum Structures and Devices
- Quantum optics and atomic interactions
- Gyrotron and Vacuum Electronics Research
- Semiconductor Lasers and Optical Devices
- Particle accelerators and beam dynamics
- Superconducting and THz Device Technology
- Particle Accelerators and Free-Electron Lasers
- Neural Networks and Reservoir Computing
- Photonic and Optical Devices
- Quantum Computing Algorithms and Architecture
Chalmers University of Technology
2010-2018
Abstract We propose and demonstrate a read-out technique for superconducting qubit by dispersively coupling it with Josephson parametric oscillator. employ tunable quarter wavelength resonator modulate its resonant frequency at twice value an amplitude surpassing the threshold instability. map states onto two distinct of classical oscillation: one oscillating state, 185±15 photons in resonator, zero oscillation amplitude. This high contrast obviates following quantum-limited amplifier....
The generation and distribution of entanglement is a central topic in quantum information science, enabling important applications communication computing. This has created great interest creating ``flying'' entangled states. authors present parametric cavity that generates multimode states microwave photons with programmable structure. advance will facilitate progress range fields, including cluster states, error-correctable logical qubits for communication, the simulation relativistic...
We characterize a novel Josephson parametric amplifier based on flux-tunable quarter-wavelength resonator. The fundamental resonance frequency is ~1GHz, but we use higher modes of the resonator for our measurements. An on-chip tuning line allows magnetic flux pumping amplifier. investigate and compare degenerate amplification, involving single mode, nondegenerate using pair modes. show that reach quantum-limited noise performance in both cases, added can be less than 0.5 photons case low gain.
We describe a circuit model for flux-driven Superconducting QUantum Interference Device (SQUID). This is useful developing insight into how these devices perform as active elements in parametric amplifiers. The key concept that frequency mixing flux-pumped SQUID allows the appearance of an effective negative resistance. In three-wave, degenerate case treated here, resistance appears only over certain range allowed input signal phase. readily lends itself to testable predictions more...
A quantum coherent interface between optical and microwave photons can be used as a basic building block within future information network.The is envisioned an ensemble of rare-earth ions coupled to superconducting resonator, allowing for transfer photons.Towards this end, we have realized hybrid device coupling Er 3+ doped Y2SiO5 crystal in coplanar waveguide cavity.We observe collective spin 4 MHz linewdith down 75 MHz.
We propose two different setups to generate single photons on demand using an atom in front of a mirror, along with either beam-splitter or tunable coupling. show that photon generation efficiency ~99% is straightforward achieve. The proposed schemes are simple and easily frequency. operation relatively insensitive dephasing can be extended correlated pairs photons. They also principle used any photonic qubit the form $\mu |0 \rangle + \nu |1\rangle$ arbitrary wave-packets, making them very...
We investigate nondegenerate parametric oscillations in a superconducting microwave multimode resonator that is terminated by quantum interference device (SQUID). The effect achieved modulating magnetic flux through the SQUID at frequency close to sum of two resonator-mode frequencies. For modulation amplitudes exceeding an instability threshold, self-sustained are observed both modes. these show good quantitative agreement with theoretical model. oscillation phases found be correlated and...
We have created a doubly tunable resonator, with the intention to simulate relativistic motion of resonator boundaries in real space. Our device is superconducting coplanar-waveguide microwave fundamental resonant frequency ω1/(2π) ~ 5 GHz. Both its ends are terminated ground via dc-SQUIDs, which serve as magnetic-flux-controlled inductances. Applying flux either SQUID allows tuning by approximately 700 MHz. Using two separate on-chip magnetic-flux lines, we modulate SQUIDs tones equal...
The design, simulation and measurements of an on-chip Mach-Zehnder interferometer operating in the microwave regime are described. Using signals microfabricated superconducting Al waveguides, concept is transferred from optics to on-chip. Tuning path length one arms executed through tunable inductance a SQUID. By placing or more SQUIDs waveguide structure by varying magnetic flux SQUID loop, total can be tuned. In this way, phase difference leading destructive constructive interference at...
In the dynamical Casimir effect (DCE), a boundary condition for electromagnetic field is changed rapidly, resulting in generation of pairs photons [1]. This was experimentally demonstrated 2011 [2]. Both and two-mode squeezing were observed. Quantum theory predicts that photon are entangled nonclassical state at zero temperature. Johansson et al. [3] recently suggested how to test entanglement DCE radiation by evaluating log negativity. Here we present such an experimental test. We have...