Photonic Networking of Trapped Ion Qubits

 
Trapped ion quantum bits can be linked through a photonic quantum channel, creating long-distance entanglement between quantum memories, quantum networks, and distributed quantum computers.

We are investigating the probabalistic entanglement of individual ions with spontaneously-emitted photons, and the creation of multiple ion/photon entangled pairs that can be measured in such a way as to produce entanglement between distant trapped ion qubit memories.  Unlike other sources of probabalistic entanglement (eg., two-photon downconversion), after verification this type of entanglement can be used as a resource for efficient scaling to even larger entangled states over many nodes.  This approach significantly relaxes conventional approaches to ion-ion entanglement, as the trapped ions need not be well-localized, and motional coherence is not relevant. 

This type of ion-ion coupling does not rely on the control of the motional state of the ions, and therefore does not require advanced cooling and small, tightly-confining traps.  The linear traps used in this project are big (0.5-1.0 mm characteristic size)

 

 

Two Cd+ ions from two separate ion-traps imaged simultaneously on a single camera:

Poster at the 2005 Gordon Conference on Atomic Physics:

 

ION PHOTON ENTANGLEMENT

Described below is a report on our group’s recent entanglement between an ideal quantum memory represented by a single trapped atomic ion, and an ideal quantum communication channel carried by a single photon.  This is the first direct observation of entanglement between stationary and “flying” qubits.  This probabilistic 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.

 

3/11/04 -  First direct observation of entanglement between single atoms and single photons.

Manuscript/News&Views description

 

RECENT PAPERS:

Quantum Networking with Photons and Trapped Atoms, D. L. Moehring, M. J. Madsen, K. C. Younge, R. N. Kohn, Jr., P. Maunz, L.-M. Duan, C. Monroe, and B. B. Blinov, J. Opt. Soc. Am. B 24, 300 (2007).

Quantum Interference of Photon Pairs from Two Trapped Atomic Ions, P. Maunz, D. L. Moehring, M. J. Madsen, R. N. Kohn, Jr., K. C. Younge, and C. Monroe, quant-ph/0608047 (2006).

Probabilistic Quantum Gates between Remote Atoms through Interference of Optical Frequency Qubits, L.-M. Duan, M. J. Madsen, D. L. Moehring, P. Maunz, R.N. Kohn, Jr., and C. Monroe, Phys. Rev. A 73, 062324 (2006).

Ultrafast Coherent Coupling of Atomic Hyperfine and Photon Frequency Qubits, M. J. Madsen, D. L. Moehring, P. Maunz, R.N. Kohn, Jr., L.-M. Duan, and C. Monroe, Phys. Rev. Lett. 97, 040505 (2006). 

Experimental Bell Inequality Violation with an Atom and a Photon, D.L. Moehring, M.J. Madsen, B.B. Blinov, and C. Monroe, Phys. Rev. Lett. 93, 090410 (2004)

Scalable Trapped Ion Quantum Computation with a Probabilistic Ion-Photon Mapping, L.-M. Duan, B.B. Blinov, D.L. Moehring, and C. Monroe, Quantum Inf. Comput. 4, 165 (2004)

Observation of Entanglement Between a Single Trapped Atom and a Single Photon, B.B. Blinov, D.L. Moehring, L.-M. Duan, and C. Monroe, Nature (London) 428, 153 (2004)

The Trap that Russ Built, by Boris Blinov

 

 

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