System and method for quantum based information transfer

• US 9,270,385 B2
• Filed: 10/09/2014
• Issued: 02/23/2016
• Est. Priority Date: 08/04/2004
• Status: Active Grant

• Current Assignee: United States Of America As Represented By The Secretary Of The Army (Government of the United States of America)
• Original Assignee: The United States Of America As Represented By The Secretary Of The Army
• Inventors: Meyers, Ronald E, Deacon, Keith S
• Primary Examiner(s): DOBSON, DANIEL G
• Application Number:
  US14/510,464
• Publication Number:
  US 20150055961A1
• Time in Patent Office: 502 Days
• US Class Current: 1/1
• CPC Class Codes: B82Y 10/00 Nanotechnology for information processing, storage or transmission, e.g. quantum computing or single electron logic
• CPC Class Codes: B82Y 20/00 Nanooptics, e.g. quantum optics or photonic crystals
• CPC Class Codes: G06N 10/00 Quantum computing, i.e. information processing based on quantum-mechanical phenomena
• CPC Class Codes: H04B 10/50 Transmitters
• CPC Class Codes: H04B 10/60 Receivers
• CPC Class Codes: H04B 10/70 Photonic quantum communication
• CPC Class Codes: H04L 9/0855 involving additional nodes, e.g. quantum relays, repeaters, intermediate nodes or remote nodes
• CPC Class Codes: Y10S 977/933 Spintronics or quantum computing

Abstract

A system for communicating data comprising sender and receiver subsystems; at least one data input; at least one entangled photon source; first photons of the pairs of entangled photons outputted by the at least one photon source being processed by one of the sender or receiver subsystem; second photons of the pairs of entangled photons being processed by the other of the sender or receiver subsystem; a photonic element configured to receive the first photons of the pairs of entangled photons and enable interference therebetween; at least one absorber configured to absorb the first photons after passage through the beam splitter, the absorbance of the first photons operating to transfer the properties of the entanglement to the second photons of the pairs of entangled photons; and a Bell state measurement element operatively associated with the receiver subsystem configured to measure the second photons of the pairs of entangled photons.

Claims

1. A system for communicating data comprising:

a sender subsystem;

a receiver subsystem;

at least one data input configured to input data into the sender subsystem;

at least one entangled photon source configured to output entangled photon pairs;

first photons of the pairs of entangled photons outputted by the at least one photon source being processed by one of the sender or receiver subsystem;

second photons of the pairs of entangled photons being processed by the other of the sender or receiver subsystem;

a photonic element configured to receive the first photons of the pairs of entangled photons and enable interference therebetween;

at least one absorber configured to absorb the first photons of the pairs of entangled photons after passage through the photonic element, the absorbance of the first photons of the pairs of entangled photons operating to transfer the properties of the entanglement to the second photons of the pairs of entangled photons; and

a Bell state measurement element operatively associated with the receiver subsystem;

the Bell state measurement element configured to measure the second photons of the pairs of entangled photons.

2. The system of claim 1 wherein one of the emission of pairs of entangled photons by the at least one entangled photon source or the reception of first photons of the pairs of entangled photons by the photonic element is controllable to enable the transmission of a message.

3. The system of claim 2 wherein the photonic element comprises a first beam splitter and wherein the at least one absorber comprises at least one detector, the at least one detector configured to measure the Bell state of the first photons of the pairs of entangled photons passing through the first beam splitter, the measured Bell state correlating to the Bell state measured by the Bell state measurement element operatively associated with the receiver.

4. The system of claim 2 further comprising an interrupt operatively associated with the photonic element configured to prevent one or more of the first photons of the pairs of entangled photons from being inputted into the photonic element;

the interrupt being adapted to be controlled by an operator or computer to transmit an encoded message.

5. The system of claim 2 wherein the interrupt is a shutter device which is configured to prevent photons from being inputted into a photonic element, the shutter device being adapted to be controlled by one of an operator or computer to transmit an encoded message.

6. The system of claim 1 further comprising at least one processor, and wherein the sender subsystem further comprises at least one processor operatively associated with the interrupt and the at least one detector, and the receiver subsystem comprises at least one processor operatively associated with the Bell state measurement element.

7. The system of claim 1 wherein the sender subsystem and receiver subsystem each further comprises at least one delay element, the at least one delay element configured to delay photons such that photons emitted from the at least one entangled photon source at different times are inputted synchronously into the photonic element operatively associated with the sender and the Bell state measurement element operatively associated with the receiver.

8. The system of claim 1 wherein the at least one entangled photon source comprises first and second entangled photon sources, the first entangled photon source being operatively associated with the sender subsystem and the second entangled photon source being operatively associated with the receiver subsystem, and wherein the at least one absorber comprises at least one detector configured to measure the Bell state, and wherein the measurement of the Bell state of the first photons of the pairs of entangled photons occurs at substantially the same time as the measurement by the Bell state measurement element operatively associated with the receiver subsystem;

and wherein delay elements are positioned within at least one of the sender or receiver subsystems to ensure coincidence of measurements of the respective Bell states.

9. The system of claim 1 wherein the sender subsystem further comprises a second beam splitter operatively associated with the at least one entangled photon source, the second beam splitter configured to split the first photons into first and second paths, the first and second paths operating to pass photons from the second beam splitter to the first beam splitter, the second path comprising a first delay element, the first delay element being configured such that first photons from the first and second paths enter the first beam splitter synchronously;

and wherein the receiver subsystem further comprises a third beam splitter operatively associated with the at least one entangled photon source the third beam splitter configured to split the second photons into third and fourth paths, the third and fourth paths operating to pass photons from the third beam splitter to the Bell state measurement element operatively associated with the receiver subsystem, the fourth path comprising a second delay element, the second delay element being configured such that second photons from the third and fourth paths enter the Bell State measurement element synchronously.

10. The system of claim 1 wherein the sender subsystem further comprises a second beam splitter and wherein the second beam splitter is configured to split the second photons of the entangled photon pairs into first and second paths, the second path including a delay element, the delay element configured to delay photons such that first photons from the first and second paths enter the first beam splitter synchronously.

11. A system for communicating data comprising:

a transmitter subsystem;

a receiver subsystem;

at least one data input configured to input data into the transmitter subsystem;

first, second and third entangled photon sources configured to output entangled photon pairs;

first photons of the pairs of entangled photons outputted by the first, second and third entangled photon sources being processed by one of the transmitter or receiver subsystems;

second photons of the pairs of entangled photons outputted by the first, second and third entangled photon sources being processed by the other of the transmitter or receiver subsystems;

a first Bell state measurement element operatively associated with the transmitter;

the first Bell state measurement element configured to measure the first photons of the pairs of entangled photons from the first and second entangled photon sources;

a second Bell state measurement element operatively associated with the receiver system;

the Bell state measurement element configured to measure the second photons of the pairs of entangled photons from the first and second entangled photon sources;

a data source for the input of information;

a third Bell state measurement element operatively associated with the transmitter, receiver and the data source, the third Bell state measurement element operative to measure photons representing data from the data source in conjunction with the one of pairs of photons from the third photon source;

a unitary transform device operatively associated with the receiver subsystem, the unitary transform device configured to receive the other of the pairs of photons from the third entangled photon source and to output photons representing data from the data source; and

an output measurement element operatively associated with the receiver;

the output measurement element configured to measure the outputted photons from the unitary transform device representing data from the data source.

12. The system of claim 11 further comprising at least one processor operatively connected to the unitary transform device and the second Bell state measurement element wherein upon being measured at the Bell state measurement element the entanglement is transferred from the first of the first photons of the pairs of entangled photons from the first and second photon sources to the second photons of the pairs of entangled photons from the first and second photon sources, and wherein the second Bell state measurement element measures the results of the swapped entanglement and transfers the results to the at least one processor which supplies the Bell state measured by the second Bell state measurement element to the unitary transform device which is used to output data from the data source.

13. The system of claim 11 wherein the photons from the first, second and third entangled photon sources are synchronously emitted.

14. The system of claim 11 further comprising at least one processor and an interrupt controlled by the at least one processor configured to prevent one or more of the first photons of the pairs of entangled photons from being measured by the first Bell state measurement device, the interrupt being operable to send an encoded message from the sender subsystem to the receiver subsystem.

15. A system for communicating data comprising:

a transmitter subsystem;

a receiver subsystem;

a data source configured to input information in the form of qubits;

the information to be transmitted from the transmitter to the receiver subsystem;

at least one entangled photon source configured to output entangled photon pairs;

first photons of the at least one entangled photon sources being inputted into the transmitter subsystem and second photons of the at least one entangled photon source being inputted into to the receiver subsystem;

a first photonic element having two inputs;

one input configured for input of a qubit from the data source and one input configured for input of a first photons of pairs of entangled photons from the at least one entangled photon source;

the first photonic element having two outputs;

first and second Bell state measurement elements operatively associated with the transmitter subsystem, each having first and second inputs and each of the first inputs operatively connected to one of the output ports of the first photonic element;

the second inputs of the first and second Bell state measurement elements configured to receive first photons from the at least one entangled photon source;

at least one processor operatively associated with the receiver subsystem; and

at least one receiver Bell state measurement element operatively associated with the receiver subsystem;

the at least one receiver Bell state measurement element configured to receive as an input at least one of the second photons of the pairs of photons from the at least one entangled photon source and provide a measurement to the at least one processor;

whereby through the process of entanglement swapping, information is transferred from the first photons to the second photons of the pairs of photons from the at least one entangled photon source, and though measurement by the at least one receiver Bell state measurement element, information is transferred from the transmitter to the receiver subsystem.

16. The system of claim 15 where the first photonic element is a beam splitter and wherein the first and second Bell state measurement devices each comprise at least one beam splitter and at least two detectors.

17. The system of claim 15 wherein the receiver subsystem comprises a unitary transform device operatively associated with the at least one processor, the unitary transform device configured to receive as input second photons of the pairs of photons from the at least one entangled photon source;

the second photons having swapped entanglement from the first photons of the pairs of photons from the at least one entangled photon source, such that qubits of data are transferred from the transmitter subsystem to the receiver subsystem through the process of swapped entanglement.

18. The system of claim 15 further comprising at least one unitary transform device operatively associated with the at least one processor, the at least one processor being configured to receive input from the at least one receiver Bell state measurement element, and wherein the at least one entangled photon source configured to output entangled photon pairs comprises first, second and third entangled photon sources;

first photons of the first entangled photon source being inputted into the photonic element and the second photons of the first entangled photon source being inputted into a unitary transform device, the unitary transform device being configured to enable the output of the information contained in the qubit in conjunction with the at least one processor.

19. The system of claim 15 further comprising a unitary transform device, and wherein the at least one entangled photon source configured to output entangled photon pairs comprises first, second and third entangled photon sources,

second photons of the pairs of entangled photons from the first entangled photon source being inputted into the unitary transform device;

first photons of the second entangled photon source being inputted into the first Bell state measurement element and the second photons of the second entangled photon source being inputted into the receiver Bell state measurement device, and

first photons of third entangled photon source being inputted the second Bell state measurement element and second photons of the third entangled photon source being inputted into the at least one receiver Bell State measurement element;

whereby upon measurement at the second Bell state measurement element of the first photons of the first entangled photon source and the first photons of the third entangled photon source;

entanglement is swapped to the second photons of the first entangled photon source at the unitary transform device and the second photons of the second and third entangled photon sources inputted into the receiver Bell state measurement element; and

the unitary transform device processes the information contained in the second photons from the first entangled photon source in conjunction with information outputted from the receiver Bell state measurement device to derive the information contained in the qubits.

20. The system of claim 15 further comprising at least one delay element controlled by the at least one processor, and wherein the first, second and receiver Bell state measurement devices are synchronously operated, and wherein the at least one processor comprises at least one first processor operatively associated with the transmitter subsystem and at least one second processor operatively associated with the receiver subsystem and wherein the first and second processors operate to control the at least one delay element.