scholarly journals Broken selection rule in the quantum Rabi model

2016 ◽  
Vol 6 (1) ◽  
Author(s):  
P. Forn-Díaz ◽  
G. Romero ◽  
C. J. P. M. Harmans ◽  
E. Solano ◽  
J. E. Mooij
Keyword(s):  
Coupling Strength ◽  
Quantum Electrodynamics ◽  
Selection Rule ◽  
Single Photon ◽  
Spectroscopic Observation ◽  
Single Atom ◽  
Superconducting Qubit ◽  
Rabi Model ◽  
The Matrix ◽  
Resonator System

Abstract Understanding the interaction between light and matter is very relevant for fundamental studies of quantum electrodynamics and for the development of quantum technologies. The quantum Rabi model captures the physics of a single atom interacting with a single photon at all regimes of coupling strength. We report the spectroscopic observation of a resonant transition that breaks a selection rule in the quantum Rabi model, implemented using an LC resonator and an artificial atom, a superconducting qubit. The eigenstates of the system consist of a superposition of bare qubit-resonator states with a relative sign. When the qubit-resonator coupling strength is negligible compared to their own frequencies, the matrix element between excited eigenstates of different sign is very small in presence of a resonator drive, establishing a sign-preserving selection rule. Here, our qubit-resonator system operates in the ultrastrong coupling regime, where the coupling strength is 10% of the resonator frequency, allowing sign-changing transitions to be activated and, therefore, detected. This work shows that sign-changing transitions are an unambiguous, distinctive signature of systems operating in the ultrastrong coupling regime of the quantum Rabi model. These results pave the way to further studies of sign-preserving selection rules in multiqubit and multiphoton models.

scholarly journals Strong coupling of a single photon to a superconducting qubit using circuit quantum electrodynamics

Nature ◽  
2004 ◽  
Vol 431 (7005) ◽  
pp. 162-167 ◽  
Author(s):  
A. Wallraff ◽  
D. I. Schuster ◽  
A. Blais ◽  
L. Frunzio ◽  
R.- S. Huang ◽  
...  
Keyword(s):  
Strong Coupling ◽  
Quantum Electrodynamics ◽  
Single Photon ◽  
Superconducting Qubit ◽  
Circuit Quantum Electrodynamics

scholarly journals Observation and stabilization of photonic Fock states in a hot radio-frequency resonator

Science ◽  
2019 ◽  
Vol 363 (6431) ◽  
pp. 1072-1075 ◽  
Author(s):  
Mario F. Gely ◽  
Marios Kounalakis ◽  
Christian Dickel ◽  
Jacob Dalle ◽  
Rémy Vatré ◽  
...  
Keyword(s):  
Radio Frequency ◽  
Quantum Electrodynamics ◽  
Single Photon ◽  
Thermal Fluctuations ◽  
Weak Field ◽  
Single Photons ◽  
Superconducting Qubit ◽  
Fock States ◽  
Wide Range ◽  
Mechanical Oscillators

Detecting weak radio-frequency electromagnetic fields plays a crucial role in a wide range of fields, from radio astronomy to nuclear magnetic resonance imaging. In quantum optics, the ultimate limit of a weak field is a single photon. Detecting and manipulating single photons at megahertz frequencies presents a challenge because, even at cryogenic temperatures, thermal fluctuations are appreciable. Using a gigahertz superconducting qubit, we observed the quantization of a megahertz radio-frequency resonator, cooled it to the ground state, and stabilized Fock states. Releasing the resonator from our control, we observed its rethermalization with nanosecond resolution. Extending circuit quantum electrodynamics to the megahertz regime, we have enabled the exploration of thermodynamics at the quantum scale and allowed interfacing quantum circuits with megahertz systems such as spin systems or macroscopic mechanical oscillators.

Quantum Effects in Single-Atom and Single-Photon Experiments

1990 ◽  
pp. 13-30
Author(s):  
G. Rempe ◽  
W. Schleich ◽  
M. O. Scully ◽  
H. Walther
Keyword(s):  
Single Photon ◽  
Quantum Effects ◽  
Single Atom

scholarly journals Multimode Cavity Optomechanics

Proceedings ◽  
2019 ◽  
Vol 12 (1) ◽  
pp. 54
Author(s):  
Paolo Piergentili ◽  
Letizia Catalini ◽  
Mateusz Bawaj ◽  
Stefano Zippili ◽  
Nicola Malossi ◽  
...  
Keyword(s):  
Relative Motion ◽  
Coupling Strength ◽  
Single Photon ◽  
Mechanical Resonators ◽  
Cavity Optomechanics ◽  
Optomechanical System ◽  
Single Membrane ◽  
Fabry Perot ◽  
Optomechanical Coupling ◽  
Photon Coupling

We study theoretically and experimentally the behavior of an optomechanical system where two vibrating dielectric membranes are placed inside a driven Fabry-Pérot cavity. We prove that multi–element systems of mechanical resonators are suitable for enhancing optomechanical performances, and we report a ∼2.47 gain in the optomechanical coupling strength of the membrane relative motion with respect to the single membrane case. With this configuration it is possible to enable cavity optomechanics in the strong single-photon coupling regime.

scholarly journals Precision laser spectroscopy experiments on antiprotonic helium

2018 ◽  
Vol 181 ◽  
pp. 01001
Author(s):  
Masaki Hori
Keyword(s):  
Laser Spectroscopy ◽  
Quantum Electrodynamics ◽  
Single Photon ◽  
Antiprotonic Helium ◽  
Doppler Width ◽  
Electron Mass ◽  
Buffer Gas ◽  
Mass Ratio ◽  
Buffer Gas Cooling ◽  
Three Body

At CERN‘s Antiproton Decelerator (AD) facility, the Atomic Spectroscopyand Collisions Using Slow Antiprotons (ASACUSA) collaboration is carrying out precise laser spectroscopy experiments on antiprotonic helium (p̅He+ ≡ p̅+He2++e−) atoms. By employing buffer-gas cooling techniquesin a cryogenic gas target, samples of atoms were cooled to temperatureT = 1.5–1.7 K, thereby reducing the Doppler width in the single-photon resonance lines. By comparing the results with three-body quantum electrodynamics calculations, the antiproton-to-electron mass ratio was determined as Mp̅/me = 1836.1526734(15). This agreed with the known proton-to-electron mass ratio with a precision of 8 . 1010. Further improvements in the experimental precision are currently being attempted. The high-quality antiproton beam provided by the future Extra Low Energy Antiproton Ring (ELENA) facility should further increase the experimental precision.

scholarly journals Logical measurement-based quantum computation in circuit-QED

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Jaewoo Joo ◽  
Chang-Woo Lee ◽  
Shingo Kono ◽  
Jaewan Kim
Keyword(s):  
Quantum Computation ◽  
Quantum Electrodynamics ◽  
Cluster State ◽  
Error Correcting Code ◽  
Microwave Cavity ◽  
Entangled State ◽  
Superconducting Qubit ◽  
Circuit Qed ◽  
Specific Protocol ◽  
Logical Qubit

Abstract We propose a new scheme of measurement-based quantum computation (MBQC) using an error-correcting code against photon-loss in circuit quantum electrodynamics. We describe a specific protocol of logical single-qubit gates given by sequential cavity measurements for logical MBQC and a generalised Schrödinger cat state is used for a continuous-variable (CV) logical qubit captured in a microwave cavity. To apply an error-correcting scheme on the logical qubit, we utilise a d-dimensional quantum system called a qudit. It is assumed that a three CV-qudit entangled state is initially prepared in three jointed cavities and the microwave qudit states are individually controlled, operated, and measured through a readout resonator coupled with an ancillary superconducting qubit. We then examine a practical approach of how to create the CV-qudit cluster state via a cross-Kerr interaction induced by intermediary superconducting qubits between neighbouring cavities under the Jaynes-Cummings Hamiltonian. This approach could be scalable for building 2D logical cluster states and therefore will pave a new pathway of logical MBQC in superconducting circuits toward fault-tolerant quantum computing.

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