Quantum information in cavity quantum electrodynamics: logical gates, entanglement engineering and ‘Schrödinger–cat states’

2003 ◽  
Vol 361 (1808) ◽  
pp. 1339-1347 ◽  
Author(s):  
S. Haroche
Keyword(s):  
Quantum Information ◽  
Quantum Electrodynamics ◽  
Cavity Quantum Electrodynamics ◽  
Schrödinger Cat ◽  
Cat States

scholarly journals Quantum optics and cavity QED with quantum dots in photonic crystals

2017 ◽  
Author(s):  
Jelena Vučković
Keyword(s):  
Quantum Dots ◽  
Information Processing ◽  
Quantum Information ◽  
Quantum Optics ◽  
Quantum Electrodynamics ◽  
Cavity Qed ◽  
Cavity Quantum Electrodynamics ◽  
Test Bed ◽  
Matter Interaction ◽  
Light Matter Interaction

Quantum dots in optical nanocavities are interesting as a test-bed for fundamental studies of light–matter interaction (cavity quantum electrodynamics, QED), as well as an integrated platform for information processing. As a result of the strong field localization inside sub-cubic-wavelength volumes, these dots enable very large emitter–field interaction strengths. In addition to their use in the study of new regimes of cavity QED, they can also be employed to build devices for quantum information processing, such as ultrafast quantum gates, non-classical light sources, and spin–photon interfaces. Beside quantum information systems, many classical information processing devices, such as lasers and modulators, benefit greatly from the enhanced light–matter interaction in such structures. This chapter gives an introduction to quantum dots, photonic crystal resonators, cavity QED, and quantum optics on this platform, as well as possible device applications.

scholarly journals Generation of multicomponent atomic Schrödinger cat states of up to 20 qubits

Science ◽  
2019 ◽  
Vol 365 (6453) ◽  
pp. 574-577 ◽  
Author(s):  
Chao Song ◽  
Kai Xu ◽  
Hekang Li ◽  
Yu-Ran Zhang ◽  
Xu Zhang ◽  
...  
Keyword(s):  
Quantum Information ◽  
Information Science ◽  
Quantum Information Processing ◽  
Ghz State ◽  
Many Body ◽  
Time Intervals ◽  
Fundamental Physics ◽  
Schrödinger Cat ◽  
Many Body Systems ◽  
Cat States

Multipartite entangled states are crucial for numerous applications in quantum information science. However, the generation and verification of multipartite entanglement on fully controllable and scalable quantum platforms remains an outstanding challenge. We report the deterministic generation of an 18-qubit Greenberger-Horne-Zeilinger (GHZ) state and multicomponent atomic Schrödinger cat states of up to 20 qubits on a quantum processor, which features 20 superconducting qubits, also referred to as artificial atoms, interconnected by a bus resonator. By engineering a one-axis twisting Hamiltonian, the system of qubits, once initialized, coherently evolves to multicomponent atomic Schrödinger cat states—that is, superpositions of atomic coherent states including the GHZ state—at specific time intervals as expected. Our approach on a solid-state platform should not only stimulate interest in exploring the fundamental physics of quantum many-body systems, but also enable the development of applications in practical quantum metrology and quantum information processing.

Controlling photons in a box and exploring the quantum to classical boundary

2014 ◽  
Vol 29 (10) ◽  
pp. 1430026
Author(s):  
Serge Haroche
Keyword(s):  
Quantum Electrodynamics ◽  
Quantum Physics ◽  
Quantum Information Processing ◽  
Ion Trap ◽  
Measurement Theory ◽  
Cavity Quantum Electrodynamics ◽  
Founding Fathers ◽  
Ideal System ◽  
Classical Boundary ◽  
Cat States

Microwave photons trapped in a superconducting cavity constitute an ideal system to realize some of the thought experiments imagined by the founding fathers of quantum physics. The interaction of these trapped photons with Rydberg atoms crossing the cavity illustrates fundamental aspects of measurement theory. The experiments performed with this "photon box" at the Ecole Normale Supérieure (ENS) belong to the domain of quantum optics called "Cavity Quantum Electrodynamics." We have realized the non-destructive counting of photons, the recording of field quantum jumps, the preparation and reconstruction of "Schrödinger cat" states of radiation and the study of their decoherence, which provides a striking illustration of the transition from the quantum to the classical world. These experiments have also led to the demonstration of basic steps in quantum information processing, including the deterministic entanglement of atoms and the realization of quantum gates using atoms and photons as quantum bits. This lecture starts with an introduction stressing the connection between the ENS photon box and the ion trap experiments of David Wineland, whose accompanying lecture recalls his own contribution to the field of single particle control. I give then a personal account of the early days of Cavity Quantum Electrodynamics before describing the main experiments performed at ENS during the last twenty years and concluding with a discussion comparing our work to other research dealing with the control of single quantum particles.

scholarly journals Deterministic amplification of Schrödinger cat states in circuit quantum electrodynamics

2016 ◽  
Vol 18 (2) ◽  
pp. 023028 ◽  
Author(s):  
Jaewoo Joo ◽  
Matthew Elliott ◽  
Daniel K L Oi ◽  
Eran Ginossar ◽  
Timothy P Spiller
Keyword(s):  
Quantum Electrodynamics ◽  
Circuit Quantum Electrodynamics ◽  
Schrödinger Cat ◽  
Cat States

Deterministically Encoding Quantum Information Using 100-Photon Schrodinger Cat States

Science ◽  
2013 ◽  
Vol 342 (6158) ◽  
pp. 607-610 ◽  
Author(s):  
B. Vlastakis ◽  
G. Kirchmair ◽  
Z. Leghtas ◽  
S. E. Nigg ◽  
L. Frunzio ◽  
...  
Keyword(s):  
Quantum Information ◽  
Schrödinger Cat ◽  
Cat States

scholarly journals Experimental quantum simulation of superradiant phase transition beyond no-go theorem via antisqueezing

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Xi Chen ◽  
Ze Wu ◽  
Min Jiang ◽  
Xin-You Lü ◽  
Xinhua Peng ◽  
...  
Keyword(s):  
Phase Transition ◽  
Quantum Electrodynamics ◽  
Statistical Physics ◽  
Zero Point ◽  
Cavity Quantum Electrodynamics ◽  
Quantum Metrology ◽  
Experimental Conditions ◽  
Physical Systems ◽  
Cat States ◽  
Superradiant Phase

AbstractThe superradiant phase transition in thermal equilibrium is a fundamental concept bridging statistical physics and electrodynamics, which has never been observed in real physical systems since the first proposal in the 1970s. The existence of this phase transition in cavity quantum electrodynamics systems is still subject of ongoing debates due to the no-go theorem induced by the so-called A2 term. Moreover, experimental conditions to study this phase transition are hard to achieve with current accessible technology. Based on the platform of nuclear magnetic resonance, here we experimentally simulate the occurrence of an equilibrium superradiant phase transition beyond no-go theorem by introducing the antisqueezing effect. The mechanism relies on that the antisqueezing effect recovers the singularity of the ground state via exponentially enhancing the zero point fluctuation of system. The strongly entangled and squeezed Schrödinger cat states of spins are achieved experimentally in the superradiant phase, which may play an important role in fundamental tests of quantum theory and implementations of quantum metrology.

scholarly journals Large array of Schrödinger cat states facilitated by an optical waveguide

2020 ◽  
Vol 11 (1) ◽  
Author(s):  
Wui Seng Leong ◽  
Mingjie Xin ◽  
Zilong Chen ◽  
Shijie Chai ◽  
Yu Wang ◽  
...  
Keyword(s):  
Quantum Information ◽  
Quantum Physics ◽  
Quantum Information Processing ◽  
Large Array ◽  
Hollow Core ◽  
Photonic Crystal Fibre ◽  
Wide Range ◽  
Schrödinger Cat ◽  
Cat States ◽  
Photon Interactions

Abstract Quantum engineering using photonic structures offer new capabilities for atom-photon interactions for quantum optics and atomic physics, which could eventually lead to integrated quantum devices. Despite the rapid progress in the variety of structures, coherent excitation of the motional states of atoms in a photonic waveguide using guided modes has yet to be demonstrated. Here, we use the waveguide mode of a hollow-core photonic crystal fibre to manipulate the mechanical Fock states of single atoms in a harmonic potential inside the fibre. We create a large array of Schrödinger cat states, a quintessential feature of quantum physics and a key element in quantum information processing and metrology, of approximately 15000 atoms along the fibre by entangling the electronic state with the coherent harmonic oscillator state of each individual atom. Our results provide a useful step for quantum information and simulation with a wide range of photonic waveguide systems.

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