# US 2023/0056032 A1 · Tractor Atom Interferometry

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- Number: US 2023/0056032 A1
- Document ID: US20230056032A1
- Status: Published application
- Kind: A1
- Application number: 17/891,673
- Filed: 2022-08-19
- Published: 2023-02-23
- Earliest claimed: 2021-08-20
- Assignees: The Regents of the University of Michigan
- Applicants: The Regents of the University of Michigan
- Inventors: Georg A. RAITHEL; Alisher DUSPAYEV
- Web page: https://patentgrep.com/patent/US20230056032A1

## CPC

- G21K 1/30: for confining neutral particles or handling confined neutral particles, e.g. atom traps
- G01C 19/58: Turn-sensitive devices without moving masses
- G01P 15/093: by photoelectric pick-up
- G21K: HANDLING OF PARTICLES OR IONISING RADIATION NOT OTHERWISE PROVIDED FOR; IRRADIATION DEVICES; GAMMA RAY OR X-RAY MICROSCOPES
- G01C: MEASURING DISTANCES, LEVELS OR BEARINGS; SURVEYING; NAVIGATION; GYROSCOPIC INSTRUMENTS; PHOTOGRAMMETRY OR VIDEOGRAMMETRY (measuring liquid level G01F; radio navigation, determining distance or velocity by use of propagation effects, e.g. Doppler effects, propagation time, of radio waves, analogous arrangements using other waves G01S)
- G01P: MEASURING LINEAR OR ANGULAR SPEED, ACCELERATION, DECELERATION, OR SHOCK; INDICATING PRESENCE, ABSENCE, OR DIRECTION, OF MOVEMENT (measuring or recording blood flow A61B5/02, A61B8/06; monitoring speed or deceleration of electrically-propelled vehicles B60L3/00; vehicle lighting systems adapted to indicate speed B60Q1/54; determining position or course in navigation, measuring ground distance in geodesy or surveying G01C; combined measuring devices for measuring two or more variables of movement G01C23/00; measuring velocity of sound G01H; measuring velocity of light G01J7/00; measuring direction or velocity of solid objects by reception or emission of radiowaves or other waves and based on propagation effects, e.g. Doppler effect, propagation time, direction of propagation, G01S; measuring speed of nuclear radiation G01T; measuring acceleration of gravity G01V; {measuring or recording the speed of trains B61L23/00; speed indicators incorporated in motor vehicles B60K35/00; measuring frequency or phase G01R; traffic control G08G})

## Abstract

A method is presented for measuring motion of a moving body using an atom interferometer. The method includes: positioning at least one atom in a cavity of the atom interferometer, where the atom interferometer is attached to the moving body; splitting the at least one atom into a pair of wave-function components; guiding the pair of wave-function components along respective paths in the cavity such that the pair of wave-function components are confined spatially along the respective paths in all degrees of freedom and without interruption; coherently recombining the pair of wave-function components into the at least one atom; and measuring a property of the at least one atom after the pair of wave-function components have been recombined into the at least one atom, where the property of the at least one atom is indicative of motion of the moving body.

## Claims

### Claim 1

A method for measuring motion of a moving body using an atom interferometer, comprising:
positioning at least one atom in a cavity of the atom interferometer, where the atom interferometer is attached to the moving body;
splitting the at least one atom into a pair of wave-function components;
guiding the pair of wave-function components along respective paths in the cavity such that the pair of wave-function components are confined spatially along the respective paths in all degrees of freedom and without interruption;
coherently recombining the pair of wave-function components into the at least one atom; and
measuring a property of the at least one atom after the pair of wave-function components have been recombined into the at least one atom, where the property of the at least one atom is indicative of motion of the moving body.

### Claim 2 (depends on 1)

The method of claim 1 further comprises positioning the at least one atom using an optical potential trap and moving the pair of wave-function components along the respective paths using the optical potential trap.

### Claim 3 (depends on 2)

The method of claim 2 further comprises splitting the at least one atom into a pair of wave-function components using pulsed microwaves or Raman laser pulses and coherently recombining the pair of wave-function components into the at least one atom using pulsed microwaves or Raman laser pulses.

### Claim 4 (depends on 1)

The method of claim 1 wherein the at least one atom is further defined as rubidium-87.

### Claim 5 (depends on 1)

The method of claim 1 further comprises measuring atomic spin states of the at least one atom and calculating acceleration of the moving body from the atomic spin state of the at least one atom.

### Claim 6

A method for measuring motion of a moving body using an atom interferometer, comprising:
positioning a plurality of atoms in a cavity of the atom interferometer, where the atom interferometer is attached to the moving body;
for each atom in the plurality of atoms, splitting a given atom into a pair of wave-function components, guiding the pair of wave-function components along respective paths in the cavity such that the pair of wave-function components are confined spatially along the respective paths in all degrees of freedom and without interruption, and coherently recombining the pair of wave-function components to reform the given atom; and
measuring a property of the plurality of atoms after the atoms have been recombined, where the property of the at least one atom is indicative of motion of the moving body.

### Claim 7 (depends on 6)

The method of claim 6 further comprises positioning the plurality of atoms using an optical potential trap and moving the pairs of wave-function components along the respective paths using the optical potential trap.

### Claim 8 (depends on 7)

The method of claim 7 further comprises splitting the plurality of atoms into multiple pairs of wave-function components using pulsed microwaves or Raman laser pulses and coherently recombining the pairs of wave-function components into the plurality of atoms using pulsed microwaves or Raman laser pulses.

### Claim 9 (depends on 6)

The method of claim 6 wherein the plurality of atoms are rubidium-87.

### Claim 10 (depends on 6)

The method of claim 6 further comprises measuring atomic spin states of the at least one atom and calculating acceleration of the moving body from the atomic spin state of the at least one atom.

### Claim 11

An atom interferometer, comprising:
an enclosure;
at least one atom position in a cavity formed in the enclosure;
two laser sources configured to project laser beams into the cavotuy and to position the at least one atom in the cavity using an optical potential trap;
a beam splitter disposed in the cavity and operates to split the at least one atom into a pair of wave-function components;
a beam combiner disposed in the cavity and operates to coherently recombining the pair of wave-function components into the at least one atom;
one or more spatial light modulators disposed in path of the laser beams projected by the two laser sources; and
a controller interfaced with the one or more spatial light modulators and operates to adjust phase of the laser beams passing therethrough and thereby translate the pair of wave-function components along respective paths in the cavity, such that the pair of wave-function components are confined spatially along the respective paths in all degrees of freedom and without interruption.

### Claim 12 (depends on 11)

The atom interferometer of claim 11 wherein the cavity is formed by two or more mirrors disposed in the enclosure.

### Claim 13 (depends on 11)

The atom interferometer of claim 11 wherein the beam splitter is further defined as a radiation source that generates pulses of electromagnetic radiation.

### Claim 14 (depends on 11)

The atom interferometer of claim 11 wherein the beam combiner is further defined as a radiation source that generates pulses of electromagnetic radiation.