Observation of entanglement between a single trapped atom and a single photon

An outstanding goal in quantum information science is the faithful mapping of quantum information between a stable quantum memory and a reliable quantum communication channel. This would allow, for example, quantum communication over remote distances, quantum teleportation of matter and distributed quantum computing over a ‘quantum internet’. Because quantum states cannot in general be copied, quantum information can only be distributed in these and other applications by entangling the quantum memory with the communication channel. Here we report quantum entanglement between an ideal quantum memory—represented by a single trapped 111Cd+ ion—and an ideal quantum communication channel, provided by a single photon that is emitted spontaneously from the ion. Appropriate coincidence measurements between the quantum states of the photon polarization and the trapped ion memory are used to verify their entanglement directly. Our direct observation of entanglement between stationary and ‘flying’ qubits is accomplished without using cavity quantum electrodynamic techniques or prepared non-classical light sources. We envision that this source of entanglement may be used for a variety of quantum communication protocols and for seeding large-scale entangled states of trapped ion qubits for scalable quantum computing.

[1]  J. A. Jacobs.  The magnetic fields of terrestrial planets , 1966 .

[2]  Matison,et al.  Experimental Test of Local Hidden-Variable Theories , 1972 .

[3]  Randall C. Thompson,et al.  Experimental Test of Local Hidden-Variable Theories , 1976 .

[4]  P. Grangier,et al.  Experimental Realization of Einstein-Podolsky-Rosen-Bohm Gedankenexperiment : A New Violation of Bell's Inequalities , 1982 .

[5]  W. I. Axford,et al.  The magnetic field of Uranus , 1986, Nature.

[6]  W. Nellis,et al.  The Nature of the Interior of Uranus Based on Studies of Planetary Ices at High Dynamic Pressure , 1988, Science.

[7]  Rainer Blatt,et al.  Quantum jumps in atomic systems , 1988 .

[8]  A. Ruzmaikin,et al.  On the Origin of Uranus and Neptune Magnetic Fields , 1991 .

[9]  W. Hubbard,et al.  Interior Structure of Neptune: Comparison with Uranus , 1991, Science.

[10]  Mario H. Acuna,et al.  The magnetic field of Neptune , 1992 .

[11]  C. Jones,et al.  Influence of the Earth's inner core on geomagnetic fluctuations and reversals , 1993, Nature.

[12]  Wineland,et al.  Young's interference experiment with light scattered from two atoms. , 1993, Physical review letters.

[13]  G. Glatzmaier,et al.  A three-dimensional convective dynamo solution with rotating and finitely conducting inner core and mantle , 1995 .

[14]  Mark S. Marley,et al.  Monte Carlo interior models for Uranus and Neptune , 1995 .

[15]  A. Longbottom,et al.  A self-consistent convection driven geodynamo model, using a mean field approximation , 1995 .

[16]  J. Cirac,et al.  Quantum Computations with Cold Trapped Ions. , 1995, Physical review letters.

[17]  Paul H. Roberts,et al.  A three-dimensional self-consistent computer simulation of a geomagnetic field reversal , 1995, Nature.

[18]  R. Brewer,et al.  Observation of superradiant and subradiant spontaneous emission of two trapped ions , 1996, Summaries of Papers Presented at the Quantum Electronics and Laser Science Conference.

[19]  Charles H. Bennett,et al.  Mixed-state entanglement and quantum error correction. , 1996, Physical review. A, Atomic, molecular, and optical physics.

[20]  R. Holme,et al.  The magnetic fields of Uranus and Neptune: Methods and models , 1996 .

[21]  R. Holme.  Three-dimensional kinematic dynamos with equatorial symmetry: Application to the magnetic fields of Uranus and Neptune , 1997 .

[22]  Jeremy Bloxham,et al.  An Earth-like numerical dynamo model , 1997, Nature.

[23]  C. Monroe,et al.  Experimental Issues in Coherent Quantum-State Manipulation of Trapped Atomic Ions , 1997, Journal of research of the National Institute of Standards and Technology.

[24]  H. Weinfurter,et al.  Experimental Entanglement Swapping: Entangling Photons That Never Interacted , 1998 .

[25]  Wolfgang Dür,et al.  Quantum Repeaters: The Role of Imperfect Local Operations in Quantum Communication , 1998 .

[26]  Thomas Pellizzari,et al.  Photon-Wavepackets as Flying Quantum Bits , 1998 .

[27]  J. Cirac,et al.  Creation of entangled states of distant atoms by interference , 1998, quant-ph/9810013.

[28]  K. Mølmer,et al.  QUANTUM COMPUTATION WITH IONS IN THERMAL MOTION , 1998, quant-ph/9810039.

[29]  E. Dormy,et al.  Numerical models of the geodynamo and observational constraints , 2000 .

[30]  D. DiVincenzo,et al.  The Physical Implementation of Quantum Computation , 2000, quant-ph/0002077.

[31]  G. Schubert,et al.  Teleconvection: remotely driven thermal convection in rotating stratified spherical layers. , 2000, Science.

[32]  C. Monroe,et al.  Experimental entanglement of four particles , 2000, Nature.

[33]  M. Horodecki,et al.  Local environment can enhance fidelity of quantum teleportation , 1999, quant-ph/9912098.

[34]  F. Busse,et al.  Regular and chaotic spherical dynamos , 2000 .

[35]  L. Mandel,et al.  Generation of spin squeezing via continuous quantum nondemolition measurement , 2000, Physical review letters.

[36]  Busse,et al.  Hemispherical dynamos generated by convection in rotating spherical shells , 2000, Physical review. E, Statistical physics, plasmas, fluids, and related interdisciplinary topics.

[37]  Gerard J. Milburn.  on "The Physics of Quantum Information: Quantum Cryptography, Quantum Teleportation, Quantum Computation" , 2001, Quantum Inf. Comput..

[38]  B. Julsgaard,et al.  Experimental long-lived entanglement of two macroscopic objects , 2001, Nature.

[39]  G. Glatzmaier,et al.  The geodynamo, past, present and future , 2001 .

[40]  J. Cirac,et al.  Long-distance quantum communication with atomic ensembles and linear optics , 2001, Nature.

[41]  Anton Zeilinger,et al.  Quantum dense coding and quantum teleportation , 2001 .

[42]  Herbert Walther,et al.  Quantum optics: The atomic nanoscope , 2001, Nature.

[43]  S. Kida,et al.  Equatorial magnetic dipole field intensification by convection vortices in a rotating spherical shell , 2002 .

[44]  Johannes Wicht.  Inner-core conductivity in numerical dynamo simulations , 2002 .

[45]  Carsten Kutzner,et al.  From stable dipolar towards reversing numerical dynamos , 2002 .

[46]  D Leibfried,et al.  Coupling a single atomic quantum bit to a high finesse optical cavity. , 2002, Physical review letters.

[47]  J J García-Ripoll,et al.  Speed optimized two-qubit gates with laser coherent control techniques for ion trap quantum computing. , 2003, Physical review letters.

[48]  C. Simon,et al.  Robust long-distance entanglement and a loophole-free bell test with ions and photons. , 2003, Physical review letters.

[49]  H. Kimble,et al.  Efficient engineering of multiatom entanglement through single-photon detections. , 2003, Physical review letters.

[50]  A. D. Boozer,et al.  Generation of nonclassical photon pairs for scalable quantum communication with atomic ensembles , 2003, Nature.

[51]  H J Kimble,et al.  State-insensitive cooling and trapping of single atoms in an optical cavity. , 2003, Physical review letters.

[52]  M. Lukin,et al.  Atomic Memory for Correlated Photon States , 2003, Science.

[53]  J. Aubert,et al.  Axial vs. equatorial dipolar dynamo models with implications for planetary magnetic fields , 2004 .

[54]  Lu-Ming Duan,et al.  Scalable trapped ion quantum computation with a probabilistic ion-photon mapping , 2004, Quantum Inf. Comput..