# US 12,216,776 B2 · Systems and methods for noise-resistant quantum communication using hyperentanglement

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- Number: US 12,216,776 B2
- Document ID: US12216776B2
- Status: Granted
- Kind: B2
- Application number: 18/700,030
- Filed: 2022-11-10
- Published: 2024-10-10
- Granted: 2025-02-04
- Earliest claimed: 2021-11-10
- Assignees: University of Maryland, College Park; Postech Research and Business Development Foundation
- Applicants: University of Maryland, College Park; Postech Research and Business Development Foundation
- Inventors: Giuliano Scarcelli; Yoon-Ho Kim; Jin-Hun Kim
- Web page: https://patentgrep.com/patent/US12216776B2

## CPC

- G06F 21/606: {by securing the transmission between two devices or processes}
- H04B 10/70: Photonic quantum communication
- G06N 10/60: Quantum algorithms, e.g. based on quantum optimisation, quantum Fourier or Hadamard transforms
- B82Y 10/00: Nanotechnology for information processing, storage or transmission, e.g. quantum computing or single electron logic
- G02F 1/212: {Mach-Zehnder type}
- G02F 1/353: {Frequency conversion, i.e. wherein a light beam is generated with frequency components different from those of the incident light beams}
- G02F 2/02: Frequency-changing of light, e.g. by quantum counters
- G06N 10/00: Quantum computing, i.e. information processing based on quantum-mechanical phenomena
- G06F: ELECTRIC DIGITAL DATA PROCESSING (computer systems based on specific computational models G06N)
- H04B: TRANSMISSION
- G06N: COMPUTING ARRANGEMENTS BASED ON SPECIFIC COMPUTATIONAL MODELS
- B82Y: SPECIFIC USES OR APPLICATIONS OF NANOSTRUCTURES; MEASUREMENT OR ANALYSIS OF NANOSTRUCTURES; MANUFACTURE OR TREATMENT OF NANOSTRUCTURES
- G02F: OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS

## Abstract

A system for noise-resistant quantum communication using hyperentanglement includes a quantum system that includes a plurality of qubits, a processor, and a memory. The memory includes instructions stored thereon, which, when executed by the processor, cause the quantum system to access a signal of a quantum system that includes a plurality of qubits and obtain hyperentanglement of the plurality of qubits via an entanglement source. The hyperentanglement of the plurality of qubits is in at least two dimensions, including a first dimension and a second dimension. The instructions, when executed, further cause the quantum system to transmit the hyperentangled plurality of qubits via a communication channel; perform a communication of the signal with the first dimension of the at least two dimensions; and filter results of the communicated signal based on the second dimension of the at least two dimensions.

## Claims

### Claim 1

A system for noise-resistant quantum communication, the system comprising:
a quantum system including a plurality of qubits;
a processor; and
a memory, including instructions stored thereon, which, when executed by the processor, cause the quantum system to:
access a signal of a quantum system;
perform hyperentanglement of the plurality of qubits via an entanglement source, wherein the hyperentanglement of the plurality of qubits is in at least two dimensions, and wherein the at least two dimensions include a first dimension and a second dimension;
transmit the hyperentangled plurality of qubits via a communication channel;
obtaining a communication of the signal with the first dimension of the at least two dimensions; and
filter results of the communicated signal based on the second dimension of the at least two dimensions.

### Claim 2 (depends on 1)

The system of claim 1, wherein the at least two dimensions include at least two separate degrees of freedom.

### Claim 3 (depends on 1)

The system according to claim 1, wherein the at least two dimensions include at least two of: polarization, frequency-time, energy-time, orbital angular momentum, time-bin, or position-momentum.

### Claim 4 (depends on 3)

The system of claim 3, wherein the entanglement source includes spontaneous parametric down-conversion.

### Claim 5 (depends on 4)

The system of claim 4, wherein the hyperentanglement is performed by spontaneous parametric down-conversion via the entanglement source.

### Claim 6 (depends on 4)

The system of claim 4, wherein the spontaneous parametric down-conversion is performed by a periodically poled Lithium Niobate crystal pumped by a second harmonic of a picosecond mode-locked fiber laser.

### Claim 7 (depends on 1)

The system of claim 1, wherein the instructions, when executed by the processor, further cause the quantum system to communicate the signal.

### Claim 8

A method for noise-resistant quantum communication, the method comprising:
accessing a signal of a quantum system, wherein the quantum system includes a plurality of qubits;
obtaining hyperentanglement of the plurality of qubits via an entanglement source, wherein the hyperentanglement of the plurality of qubits is in at least two dimensions, wherein the at least two dimensions include a first dimension and a second dimension;
transmitting the hyperentangled plurality of qubits via a communication channel;
performing a communication of the signal with the first dimension of the at least two dimensions;
filtering results of the communicated signal based on the second dimension of the at least two dimensions; and
communicating the filtered results of the communicated signal.

### Claim 9 (depends on 8)

The method of claim 8, wherein the two dimensions include at least two separate degrees of freedom.

### Claim 10 (depends on 8)

The method of claim 8, wherein the two dimensions include polarization and frequency-time,
wherein the qubits include polarization-frequency hyperentangled photon pairs, and
wherein the method further includes:
discretizing a correlated spectra of the polarization-frequency hyperentangled photon pairs into a correlated frequency bin measurement and a correlated time-bin measurement; and
deterministically mapping the correlated frequency bin measurement to the correlated time-bin measurement.

### Claim 11 (depends on 8)

The method of claim 8, wherein the qubits include signal entangled photons, and wherein the method further includes distinguishing noise photons from signal entangled photons.

### Claim 12

A non-transitory computer-readable storage medium storing a program for causing a quantum system to execute a method for noise-resistant quantum communication, the method comprising:
accessing a signal of a quantum system, the quantum system includes a plurality of qubits;
obtaining hyperentanglement of the plurality of qubits via an entanglement source, wherein the hyperentanglement of the plurality of qubits is in at least two dimensions, wherein the at least two dimensions include a first dimension and a second dimension;
transmitting the hyperentangled plurality of qubits via a noisy quantum channel;
performing a communication of the signal with the first dimension of the at least two dimensions;
filtering results of the communicated signal based on the second dimension of the at least two dimensions; and
communicating the filtered results of the communicated signal.