Determining a modal amplitude of an inhomogeneous field with a quantum sensor

1. A process for determining a modal amplitude of an inhomogeneous field of an analyte, the process comprising:

preparing an initial entangled state of a quantum sensor, the initial entangled state comprising:

a first quantum level; and

a second quantum level,

the initial entangled state being an initial linear superposition of the first quantum level and the second quantum level, and

the quantum sensor comprising a plurality of qudit sensors in which each qudit sensor comprises an energy difference between a plurality of quantum levels of the qudit sensor, the energy difference being linearly dependent on a strength of the inhomogeneous field;

subjecting the quantum sensor to the inhomogeneous field of the analyte;

subjecting a first qudit sensor of the quantum sensor to a first perturbation pulse;

receiving the first perturbation pulse by the first qudit sensor to prepare a first intermediate entangled state of the quantum sensor, the first intermediate entangled state comprising a first intermediate linear superposition;

changing the initial linear superposition to the first intermediate linear superposition in response to receiving the first perturbation pulse by the quantum sensor; and

determining a final entangled state of the quantum sensor after applying the first perturbation pulse to determine the modal amplitude of the inhomogeneous field of the analyte.

2. The process of claim 1 , wherein qudits comprise a qubit, a qutrit, or a combination comprising at least one of the foregoing qudits.

3. The process of claim 1 , wherein qudits comprise a neutral atom, an ion, a molecule, a solid-state defect, a superconducting circuit, or a combination comprising at least one of the foregoing qudits.

4. The process of claim 1 , wherein the qudits comprise:

a first qutrit sensor; and

a second qutrit sensor,

wherein the initial entangled state is

1

2

⁡

[



00

〉

+



11

〉

]

,

and

the final entangled state, after final evolution under coupling to the inhomogeneous field of the analyte, is

1

2

⁡

[



00

〉

+

e

-

i

⁢

⁢

t

f

⁢

q

⁢



21

〉

]

.

5. The process of claim 1 , wherein the qudits comprise:

a first qubit sensor; and

a second qubit sensor;

a third qubit sensor;

wherein the initial entangled state is

1

2

⁡

[



000

〉

+



111

〉

]

,

the intermediate entangled state comprises

1

2

⁡

[



100

〉

+

e

-

i

⁢

⁢

ϑ

2

⁢



011

〉

]

,

and

the final entangled state, after final evolution under coupling to the inhomogeneous field of the analyte, comprises

1

2

⁡

[



110

〉

+

e

-

i

⁢

⁢

t

f

⁢

q

⁢



001

〉

]

.

6. The process of claim 1 , wherein the modal amplitude q comprises a linear combination of a plurality of mode components α i of a mode A and a plurality of energy components θi as

q

=

∑

i

N

⁢

α

i

⁢

θ

i

,

wherein N is a total number of qudits, and i is an integer from 1 to N.

7. The process of claim 1 , wherein the first perturbation pulse comprises a termination pulse, an echo pulse, or a combination comprising at least one of the foregoing perturbation pulses.

8. The process of claim 1 , further comprising:

subjecting a second qudit sensor of the quantum sensor to a second perturbation pulse;

receiving the second perturbation pulse by the second qudit sensor to prepare a second intermediate entangled state of the quantum sensor, the second intermediate entangled state comprising a second intermediate linear superposition;

changing the first intermediate linear superposition to the second intermediate linear superposition in response to receiving the second perturbation pulse by the quantum sensor; and

determining the final entangled state of the quantum sensor after applying the second perturbation pulse to determine the modal amplitude of the inhomogeneous field of the analyte.

9. The process of claim 1 , wherein subjecting the first qudit sensor to the first perturbation pulse occurs at a time based on a smallest mode component of mode A.

10. The process of claim 1 , wherein preparing the initial entangled state of the quantum sensor comprises subjecting the qudits to direct interaction among the qudits.

11. The process of claim 1 , wherein preparing the initial entangled state of the quantum sensor comprises subjecting the qudits to a mediator comprising a photon, a phonon, or a combination comprising at least one of the foregoing mediators.

12. The process of claim 1 , wherein the analyte comprises a planet, an organism, a tissue, a cell, a molecule, an atom, or a combination comprising at least one of the foregoing analytes.

13. The process of claim 1 , wherein the inhomogeneous field comprises an electric field, a magnetic field, a temperature, a gravitational field, a strain, or a combination comprising at least one of the foregoing inhomogeneous films.

14. The process of claim 1 , wherein determining the final entangled state of the quantum sensor after applying the first perturbation pulse comprises:

subjecting the quantum sensor to probe radiation; and

detecting whether the quantum sensor emits signal radiation in response to the probe radiation.

15. The process of claim 14 , wherein the modal amplitude q is determined according to

〈

Ψ

⁢



∏

i

=

1

N

⁢

σ

i

x

⁢

q



⁢

Ψ

〉

=

cos

⁡

(

qt

f

)

,

wherein Ψ is a quantum state of the quantum sensor at a final time t f and σ i x is a Pauli x operator acting on qubit i.

16. A computer-implemented method for determining a modal amplitude of an inhomogeneous field of an analyte, the method comprising:

preparing an initial entangled state of a quantum sensor, the initial entangled state comprising:

a first quantum level;

a second quantum level; and

an energy difference between the second quantum level and the first quantum level, the energy difference being linearly dependent on a strength of the inhomogeneous field,

the initial entangled state being an initial linear superposition of the first quantum level and the second quantum level, and

the quantum sensor comprising a plurality of qudit sensors;

subjecting the quantum sensor to the inhomogeneous field of the analyte;

subjecting a first qudit sensor of the quantum sensor to a first perturbation pulse;

receiving the first perturbation pulse by the first qudit sensor to prepare a first intermediate entangled state of the quantum sensor, the first intermediate entangled state comprising a first intermediate linear superposition;

changing the initial linear superposition to the first intermediate linear superposition in response to receiving the first perturbation pulse by the quantum sensor; and

determining a final entangled state of the quantum sensor after applying the first perturbation pulse to determine the modal amplitude of the inhomogeneous field of the analyte.

17. A system comprising:

one or more computers configured to perform operations, the operations for determining a modal amplitude of an inhomogeneous field of an analyte, comprising:

preparing an initial entangled state of a quantum sensor, the initial entangled state comprising:

a first quantum level;

a second quantum level; and

an energy difference between the second quantum level and the first quantum level, the energy difference being linearly dependent on a strength of the inhomogeneous field,

the initial entangled state being an initial linear superposition of the first quantum level and the second quantum level, and

the quantum sensor comprising a plurality of qudit sensors;

subjecting the quantum sensor to the inhomogeneous field of the analyte;

subjecting a first qudit sensor of the quantum sensor to a first perturbation pulse;

receiving the first perturbation pulse by the first qudit sensor to prepare a first intermediate entangled state of the quantum sensor, the first intermediate entangled state comprising a first intermediate linear superposition;

changing the initial linear superposition to the first intermediate linear superposition in response to receiving the first perturbation pulse by the quantum sensor; and

determining a final entangled state of the quantum sensor after applying the first perturbation pulse to determine the modal amplitude of the inhomogeneous field of the analyte.

18. A non-transitory computer-readable medium instructions stored thereon, which, when executed by a processor, cause the processor to perform operations for determining a modal amplitude of an inhomogeneous field of an analyte, the operations comprising:

preparing an initial entangled state of a quantum sensor, the initial entangled state comprising:

a first quantum level;

a second quantum level; and

an energy difference between the second quantum level and the first quantum level, the energy difference being linearly dependent on a strength of the inhomogeneous field,

the initial entangled state being an initial linear superposition of the first quantum level and the second quantum level, and

the quantum sensor comprising a plurality of qudit sensors;

subjecting the quantum sensor to the inhomogeneous field of the analyte;

subjecting a first qudit sensor of the quantum sensor to a first perturbation pulse;

receiving the first perturbation pulse by the first qudit sensor to prepare a first intermediate entangled state of the quantum sensor, the first intermediate entangled state comprising a first intermediate linear superposition;

changing the initial linear superposition to the first intermediate linear superposition in response to receiving the first perturbation pulse by the quantum sensor; and

determining a final entangled state of the quantum sensor after applying the first perturbation pulse to determine the modal amplitude of the inhomogeneous field of the analyte.