Manipulating quantum entanglement with atoms and photons in a cavity

• DOI: 10.1103/revmodphys.73.565
• Publication Date: 2002-07-27T02:32:38Z
• Authors: J. M. Raimond; M. Brune; S. Haroche
• Keywords: Quantum teleportation; Quantum sensor

After they have interacted, quantum particles generally behave as a single nonseparable entangled system. The concept of entanglement plays an essential role in physics. We performed experiments with Rydberg atoms and microwave photons cavity tested mechanics situations increasing complexity. Entanglement resulted either from resonant exchange energy between the field or dispersive shifts affecting when were not resonant. With two (two one atom photon), we realized new versions Einstein-Podolsky-Rosen situation. detection particle projected other, at distance, correlated state. This process could be viewed elementary measurement, being ``meter'' measuring other. ``quantum nondemolition'' measurement photon, which detected repeatedly without destroying it. is also to understand decoherence, accounting for classical appearance macroscopic world. A mesoscopic superposition states (``Schr\"odinger cat'') gets rapidly its environment, losing coherence. prepared Schr\"odinger cat made few studied dynamics experiment constitutes glimpse quantum/classical boundary. investigated resource processing information. By using two-state systems (qubits) instead bits information, can perform logical operations exploiting interferences taking advantage properties entanglement. Manipulating qubits cavity, operated gate applied it generation complex three-particle finally discuss perspectives opened by these further fundamental studies.