Bryan C Jacobs

US Patent:

6789043, Sep 7, 2004

Filed:

Sep 23, 1999

Appl. No.:

09/401701

Inventors:

Carl V. Nelson - Rockville Road MD
Bryan C. Jacobs - Sykesville MD

Assignee:

The Johns Hopkins University - Baltimore MD

International Classification:

G01B 714

US Classification:

702152, 702 38, 702 57, 702 65, 702 94, 702127, 702150

Abstract:

The position, orientation, velocity and acceleration of remote sensors is determined using magnetic fields. Multiple, arbitrarily oriented magnetic field transmitters are placed in one reference frame (source reference frame), and multiple, arbitrarily oriented magnetic field receivers are placed in a second reference frame (body reference frame). The spatially varying magnetic fields of the transmitters in the source reference frame are sensed by the magnetic field receivers in the body reference frame. The computer algorithm uses a physics-based extended Kalman filter to resolve the position; orientation, velocity and acceleration of the body relative to the source reference frame. The physics-based extended Kalman filter can accommodate the effects of metal in the source and body reference frames and thus allow the system to measure position, orientation, velocity and acceleration under conditions where eddy currents would normally hinder other magnetic position measuring systems. The Kalman filter also allows the use of multiple transmitters and receivers distributed over an arbitrarily large sensing volume, thereby extending the useful range and accuracy of the system. Further, the Kalman filter allows the use of high-speed measurements with minimal signal averaging, thus extending the useful dynamic response of the system.

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:

7019875, Mar 28, 2006

Filed:

Aug 12, 2003

Appl. No.:

10/639559

Inventors:

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

Assignee:

The John Hopkins University - Baltimore MD

International Classification:

G06E 3/00

US Classification:

359107, 359108, 708191

Abstract:

An optical switch and optical storage loop are used as the basis of a single-photon source and a quantum memory for photonic qubits. To operate as a single-photon source, the techniques include a source of a pair of photons, such as a parametric down-conversion crystal, which is known to emit photons in pairs. The detection of one member of the pair activates the switch, which re-routes the other member into the storage loop. The stored photon is then known to be circulating in the loop, and can be switched out of the loop at a later time chosen by the user, providing a single photon for potential use in a variety of quantum information processing applications. To operate as a quantum memory for photonic qubits, a single-photon in an arbitrary initial polarization state is coherently stored in the loop, and coherently switched out of the loop when needed.

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.

US Patent:

20030086138, May 8, 2003

Filed:

Nov 1, 2002

Appl. No.:

10/286735

Inventors:

Todd Pittman - Catonsville MD, US
James Franson - Ellicott City MD, US
Bryan Jacobs - Sykesville MD, US

International Classification:

G02F003/00

US Classification:

359/108000

Abstract:

A method and apparatus for performing logic operations using quantum polarization states of single photons, include a first polarizing beam splitter having first input spatial modes and first output spatial modes for a first set of orthogonal polarizations. A second polarizing beam splitter has a second input spatial mode and second output spatial modes for a second set of orthogonal polarizations. The second set of orthogonal polarizations is different from the first set. The second input spatial mode is aligned with a first detected output spatial mode. A single photon detector of multiple single photon detectors is disposed along each one of the second output spatial modes. A first device output carries an output photon based in part on a number of photons detected by the single photon detectors. Such logic operations may be used in quantum computers for quantum information processing.

US Patent:

20060164706, Jul 27, 2006

Filed:

Mar 27, 2006

Appl. No.:

11/390028

Inventors:

Todd Pittman - Catonsville MD, US
James Franson - Ellicott City MD, US
Bryan Jacobs - Sykesville MD, US

International Classification:

G06E 3/00

US Classification:

359107000, 359108000

Abstract:

An optical switch and optical storage loop are used as the basis of a single-photon source and a quantum memory for photonic qubits. To operate as a single-photon source, the techniques include a source of a pair of photons, such as a parametric down-conversion crystal, which is known to emit photons in pairs. The detection of one member of the pair activates the switch, which re-routes the other member into the storage loop. The stored photon is then known to be circulating in the loop, and can be switched out of the loop at a later time chosen by the user, providing a single photon for potential use in a variety of quantum information processing applications. To operate as a quantum memory for photonic qubits, a single-photon in an arbitrary initial polarization state is coherently stored in the loop, and coherently switched out of the loop when needed.

US Patent:

20130315395, Nov 28, 2013

Filed:

May 25, 2012

Appl. No.:

13/480554

Inventors:

Bryan C. Jacobs - Sykesville MD, US

Assignee:

THE JOHNS HOPKINS UNIVERSITY - Baltimore MD

International Classification:

H04L 9/08
H04L 9/00

US Classification:

380278, 380 44

Abstract:

In methods and systems to authenticate systems in a quantum key distribution environment based on limited disclosures and identical, re-usable, pre-provisioned authentication keys, each system constructs an encryption key based on a corresponding one of transmitted events and detected events. Basis-sifting, error detection, error correction, and/or privacy amplification (PA) may be performed on the encryption keys based on limited disclosures (e.g., detection interval information, basis-sifting information, associated detection basis information, and/or parity measures). The authenticated keys may be modified based on disclosed detection information. Error detection and/or PA may be performed with identical pre-provisioned algorithms and pseudo-random values generated from the authenticated keys or modified authenticated keys. Final authenticated encryption keys are selectively constructed depending upon an extent of detected errors. Construction of authenticated encryption keys indicates authentication of the systems. None of the pre-provisioned authentication keys or modified authentication keys is disclosed and may thus be reused.