Bryan W Jacobs

US Patent:

6995404, Feb 7, 2006

Filed:

Jun 29, 2004

Appl. No.:

10/879853

Inventors:

James D. Franson - Ellicott City MD, US
Bryan C. Jacobs - Sykesville MD, US
Todd B. Pittman - Ellicott City MD, US

Assignee:

The Johns Hopkins University - Baltimore MD

International Classification:

H01L 29/22

US Classification:

257 98, 257 79, 359107, 359108, 708191, 708816, 708831

Abstract:

Techniques are provided that use the quantum Zeno effect to implement practical devices that use single photons as the qubits for quantum information processing. In the quantum Zeno effect, a randomly-occurring event is suppressed by frequent measurements to determine whether the event has occurred. The same results can be obtained by using atoms or molecules or ions to react to the occurrence of the event. Techniques include directing one or more input qubits onto a device and applying a quantum Zeno effect in the device. The quantum Zeno effect is applied by consuming one or more photons in the device under conditions in which photons, that would otherwise be output by the device, do not represent a result of a particular quantum information processing operation. Devices implemented using the quantum Zeno effect can operate with low error rates without the need for high efficiency detectors and large number of ancilla.

US Patent:

7006267, Feb 28, 2006

Filed:

Aug 28, 2003

Appl. No.:

10/651317

Inventors:

James D. Franson - Ellicott City MD, US
Michelle M. Donegan - Columbia MD, US
Michael J. Fitch - Catonsville MD, US
Bryan C. Jacobs - Sykesville MD, US
Todd B. Pittman - Catonsville MD, US

Assignee:

The Johns Hopkins University - Baltimore MD

International Classification:

G06E 3/00

US Classification:

359107, 708191, 380278

Abstract:

Techniques for high fidelity quantum teleportation include receiving an input photon representing a qubit. Ancilla photons are generated in a particular ancilla quantum state chosen to reduce a rate of error below a threshold error rate. The ancilla and the input photon are combined to populate output channels. A number of photons representing logical value 1 are measured in a subset of the output channels. A particular output channel is determined based on the measured number of photons. A teleported photon is obtained at the particular output channel with an error rate below the threshold error rate. These techniques allow the ancilla quantum state to be chosen to minimize the error despite the presence of losses and noise. Quantum logic operations are performed by teleporting two input qubits with the quantum state of the ancilla chosen to produce the desired logical result and reduce the error.

US Patent:

7236667, Jun 26, 2007

Filed:

Jan 31, 2006

Appl. No.:

11/343409

Inventors:

James D. Franson - Ellicott City MD, US
Bryan C. Jacobs - Sykesville MD, US
Todd B. Pittman - Columbia MD, US

Assignee:

The Johns Hopkins University - Baltimore MD

International Classification:

G02B 6/34
G06E 1/04
H01L 33/00

US Classification:

385 37, 708191, 708250, 708816, 257 79, 257 98, 369107, 369108

Abstract:

Techniques are provided for placing atoms inside an appropriate nanocavity for enhancing two-photon absorption and quantum information processing based on the Zeno effect. Techniques for fabricating suitable nanocavities include: 1) a short length of optical fiber polished on the ends with the ends coated to form suitable mirrors; 2) a continuous length of fiber with the equivalent of mirrors being formed within the fiber using Bragg gratings; 3) a single filament of glass (such as fused silica) being suspended between two mirrors (without any cladding) and surrounded by an atomic vapor, solid, or liquid; 4) a small glass sphere (such as fused silica) that has been melted on the end of an optical fiber; and 5) a small toroid (ring) of glass bent in a circle surrounded by suitable atoms.