# US 2021/0279628 A1 · Transport-based qubit-array loading

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- Number: US 2021/0279628 A1
- Document ID: US20210279628A1
- Status: Published application
- Kind: A1
- Application number: 16/998,142
- Filed: 2020-08-20
- Published: 2021-09-09
- Earliest claimed: 2020-03-07
- Assignees: ColdQuanta, Inc.
- Applicants: ColdQuanta, Inc.
- Inventors: Thomas William NOEL; Mark SAFFMAN
- Web page: https://patentgrep.com/patent/US20210279628A1

## CPC

- G06N 10/40: Physical realisations or architectures of quantum processors or components for manipulating qubits, e.g. qubit coupling or qubit control
- G06N: COMPUTING ARRANGEMENTS BASED ON SPECIFIC COMPUTATIONAL MODELS

## Abstract

When a molecule is lost from a site of a qubit array, the site can be identified as a “target” site. A target site can be reloaded by transporting a molecule from a reservoir at least two millimeters to the target site. Alternatively, in response to the identifying, a molecule that has been transferred from the reservoir to a qubit-array region including the qubit array can be transferred to the target site. Quantum-logic language (QLL) programs can continue qubit operations on the array during transfers from the reservoir to the qubit region. Such operations can also continue during transfer from within the qubit region to a target site; in some cases, these latter operations are limited to sections of the qubit array not including a target site.

## Claims

### Claim 1

A qubit-array system comprising:
a qubit array trap including a qubit-site array of qubit sites and configured to trap cold molecules in respective ones of the qubit sites so as to define a qubit array, the qubit-array trap being located in a qubit-array region;
a reservoir trap located outside the qubit-array region and configured to trap a molecules;
a site identifier configured to identify a proper target subset of a set of qubit sites in the qubit-site array, the target subset including one or more target sites; and
a transport module configured to, in response to the identifying:
transport molecules at least two millimeters from the reservoir trap to a target site, or
transport a molecule that has been transported from the reservoir trap into the qubit-array region to a respective one of the target sites.

### Claim 2 (depends on 1)

The qubit array system of claim 1 wherein the reservoir trap is spaced at least 2 mm from the qubit-array region.

### Claim 3 (depends on 1)

The qubit array system of claim 1 wherein the reservoir is spaced at least 1 0 mm from the qubit array region.

### Claim 4 (depends on 3)

The qubit array system of claim 3 wherein the reservoir trap is spaced at most 100 mm from the qubit-array region.

### Claim 5 (depends on 1)

The qubit array system of claim 1 wherein a target site is vacant due to the loss of a molecule from that site.

### Claim 6 (depends on 1)

The qubit array system of claim 1 wherein the target site has been vacated due to removal of a molecule from that site to a neighboring site as part of a bucket-brigade procedure to fill another target site from which a molecule was lost prior to the identifying.

### Claim 7 (depends on 1)

The qubit-array system of claim 1 wherein the transport module is configured to transport molecules from the reservoir trap to the qubit-array region during qubit-array runtime.

### Claim 8 (depends on 7)

The qubit-array system of claim 7 wherein the transport module is configured to preclude, during qubit-array runtime, transport of a molecule that has been transported from the reservoir trap into the qubit-array region to a target qubit site.

### Claim 9 (depends on 1)

The qubit-array system of claim 1 wherein the transport module is configured to provide for transport of a molecule that has been transported from the reservoir trap into the qubit region to a target qubit site while a program manipulates qubit values of molecules in a section of the qubit array not including a target site.

### Claim 10 (depends on 9)

The qubit-array system of claim 9 wherein the transport module is configured to preclude transport of a molecule that has been transported from the reservoir trap into the qubit region to a target qubit site while a program manipulates qubit values of molecules in a section of the qubit array including the target site.

### Claim 11 (depends on 1)

The qubit-array system of claim 1 wherein the transport module is configured to use multiple tweezers concurrently.

### Claim 12 (depends on 11)

The qubit-array system of claim 11 wherein the transport module is configured to use the multiple tweezers to implement concurrent or pipelined loading of molecules into respective target sites.

### Claim 13 (depends on 1)

The qubit-array system of claim 1 wherein the transport module is configured to use bucket-brigade loading of a molecule into target site.

### Claim 14 (depends on 1)

The qubit-array system of claim 1 wherein the molecules are monatomic molecules.

### Claim 15 (depends on 14)

The qubit-array system of claim 14 wherein the monatomic molecules are neutral atoms.

### Claim 16 (depends on 15)

The qubit-array system of claim 15 wherein the neutral atoms are of alkali or alkaline-earth elements.

### Claim 17 (depends on 1)

The qubit array system of claim 1 wherein the site-identifier provides for non-destructive imaging of the array so as to avoid disturbing the states of molecules in non-vacant sites in the array.

### Claim 18 (depends on 1)

The qubit array system of claim 1 wherein the transport module is configured to cool molecules as they are transported from the reservoir.

### Claim 19 (depends on 1)

The qubit array system of claim 1 wherein the qubit-array is structured so as to define a transport path to the target site.

### Claim 20 (depends on 19)

The qubit array system of claim 19 wherein the qubit-array is structured temporarily by compressing rows or columns of the array.

### Claim 21 (depends on 1)

The qubit array system of claim 1 further comprising transmissive materials configured to reduce reflections of light from the reservoir region into the qubit-array region.

### Claim 22 (depends on 1)

The qubit array system of claim 1 further comprising absorbent materials to absorb light that otherwise could escape the reservoir region into the qubit-array region.

### Claim 23 (depends on 1)

The qubit array system of claim 1 further comprising gas mitigation using pumps on either side of a pressure-differential aperture between the reservoir trap and the qubit-array region.

### Claim 24 (depends on 1)

The qubit array system of claim 1 wherein the transport module includes an intra-region transport module that uses optical tweezers, crossed acousto-optic deflectors, multi-channel acousto-optic deflectors, spatial-light modulators, electro-optic modulators or liquid crystal modulators.

### Claim 25 (depends on 1)

The qubit array system of claim 1 wherein the transport of a molecule to a target site is partially along a plane through all qubit-sites of the qubit-site array.

### Claim 26 (depends on 1)

The qubit array system of claim 1 wherein the transport of a molecule to a target site is partially parallel to a plane through all qubit sites of the qubit-site array.

### Claim 27 (depends on 26)

The qubit array system of claim 26 wherein the transport of the molecule to the target site is partially orthogonal to the plane through all qubit sites of the qubit-site array.

### Claim 28

A qubit-array loading process comprising:
transporting molecules from a reservoir trap into a qubit-array region, the qubit-array region containing a qubit-site array, the qubit-site array containing a set of qubit sites, the reservoir trap being located in a reservoir region;
identifying a proper target subset of the set of qubit sites, the target subset including one or more target qubit sites; and
in response to the identifying, transporting
a molecule from the reservoir trap a distance of at least two millimeters to a respective target site, or
a molecule that has been transported from the reservoir trap into the qubit region to a respective target site.

### Claim 29 (depends on 28)

The qubit array loading process of claim 28 wherein transporting from the reservoir trap to the qubit-array region is over a distance of at least 2 mm.

### Claim 30 (depends on 28)

The qubit array loading process of claim 28 wherein the transporting from the reservoir trap to the qubit-array region is over a distance of at least 10 mm.

### Claim 31 (depends on 30)

The qubit array loading process of claim 30 wherein the reservoir trap is spaced at most 100 mm from the qubit-array region.

### Claim 32 (depends on 28)

The qubit array loading process of claim 28 wherein a target site is vacant for the duration of the transport from within the qubit-array region to the target site.

### Claim 33 (depends on 28)

The qubit array loading process of claim 28 wherein the target site has been vacated due to removal of a molecule from that site to a neighboring site as part of a bucket-brigade procedure to fill another target site that was vacated due to loss of a molecule from the array.

### Claim 34 (depends on 28)

The qubit-array loading process of claim 28 wherein transporting molecules from the reservoir trap to the qubit-array region occurs during qubit-array runtime.

### Claim 35 (depends on 34)

The qubit-array loading process of claim 34 wherein the transporting precludes, during qubit-array runtime, transport to a target site of a molecule that has been transported from the reservoir trap into the qubit region.

### Claim 36 (depends on 28)

The qubit-array system of claim 28 wherein the transporting includes manipulating qubit values of molecules located in sections of the qubit array not including a target site while a molecule is transported to a target site.

### Claim 37 (depends on 36)

The qubit-array system of claim 36 wherein the transporting precludes transport of a molecule that has been transported from the reservoir trap into the qubit region to a target site while a program manipulates qubit values of molecules in a section of the qubit array including the target site.

### Claim 38 (depends on 28)

The qubit-array loading process of claim 28 wherein the transporting includes using multiple tweezers concurrently.

### Claim 39 (depends on 38)

The qubit-array loading process of claim 38 wherein the transporting uses the multiple tweezers to implement concurrent or pipelined loading of molecules into respective target sites.

### Claim 40 (depends on 28)

The qubit-array loading process of claim 28 wherein the transporting includes loading of a molecule into a target site using a bucket-brigade procedure.

### Claim 41 (depends on 28)

The qubit-array loading process of claim 28 wherein the molecules are monatomic molecules.

### Claim 42 (depends on 41)

The qubit-array loading process of claim 41 wherein the monatomic molecules are neutral atoms.

### Claim 43 (depends on 42)

The qubit-array loading process of claim 42 wherein the neutral atoms are of alkali or alkaline-earth elements.

### Claim 44 (depends on 28)

The qubit array loading process of claim 28 wherein the identifying includes using non-destructive imaging of the array so as to avoid disturbing the states of molecules in non-vacant sites in the array.

### Claim 45 (depends on 28)

The qubit array loading process of claim 28 wherein the transporting includes cooling molecules as they are transported from the reservoir.

### Claim 46 (depends on 28)

The qubit array loading process of claim 28 wherein the qubit-array is structured so as to define a transport path to the target site.

### Claim 47 (depends on 46)

The qubit array loading process of claim 46 wherein the qubit-array is structured temporarily by compressing rows or columns of the array.

### Claim 48 (depends on 28)

The qubit array loading process of claim 28 further comprising transmitting light through transmissive materials to reduce reflections of light from the reservoir region into the qubit-array region.

### Claim 49 (depends on 28)

The qubit array loading process of claim 28 further comprising absorbing, by absorbent materials, light that otherwise could escape the reservoir region into the qubit-array region.

### Claim 50 (depends on 28)

The qubit array loading process of claim 28 further comprising mitigating gas using pumps on either side of a pressure-differential aperture between the reservoir trap and the qubit-array region.

### Claim 51 (depends on 28)

The qubit array loading process of claim 28 wherein the transporting uses optical tweezers, crossed acousto-optic deflectors, multi-channel acousto-optic deflectors, spatial-light modulators, electro-optic modulators or liquid crystal modulators.

### Claim 52 (depends on 28)

The qubit array loading process of claim 28 wherein the transport of a molecule to a target site is partially along a plane through all qubit-sites of the qubit-site array.

### Claim 53 (depends on 28)

The qubit array loading process of claim 28 wherein the transport of a molecule to a target site is partially parallel to a plane through all qubit sites of the qubit-site array.

### Claim 54 (depends on 53)

The qubit array loading process of claim 53 wherein the transport of the molecule to the target site is partially orthogonal to the plane through all qubit sites of the qubit-site array.