Transport-based qubit-array loading
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.
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 molecules;
an inter-region transport module configured to generate a moving standing wave of light to transport a cold molecule from the reservoir trap into a loading zone of the qubit-array region; and
optical tweezers configured to transport a cold molecule from the loading zone of the qubit-array region to a target qubit site of the qubit-site array.
2 . The qubit-array system of claim 1 , wherein the reservoir trap is spaced at least 2 mm from the qubit-array region.
3 . The qubit-array system of claim 1 , wherein the reservoir trap is spaced at least 10 mm from the qubit-array region.
4 . The qubit-array system of claim 3 , wherein the reservoir trap is spaced at most 100 mm from the qubit-array region.
5 . The qubit-array system of claim 1 , wherein a target site is vacant due to a loss of a molecule from that site.
6 . The qubit-array system of claim 1 , wherein the target qubit 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.
7 . The qubit-array system of claim 1 , wherein the optical tweezers are configured to provide for transport of a molecule that has been transported from the reservoir trap into the qubit-array 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.
8 . The qubit-array system of claim 7 , wherein the optical tweezers are configured to use multiple tweezers concurrently.
9 . The qubit-array system of claim 8 , wherein the optical tweezers are configured to use the multiple tweezers to implement concurrent or pipelined loading of molecules into respective target sites.
10 . The qubit-array system of claim 7 , wherein the optical tweezers are configured to use bucket-brigade loading of a molecule into target site.
11 . The qubit-array system of claim 1 , wherein the molecules are monatomic molecules.
12 . The qubit-array system of claim 11 , wherein the monatomic molecules are neutral atoms.
13 . The qubit-array system of claim 12 , wherein the neutral atoms are of alkali or alkaline-earth elements.
14 . The qubit-array system of claim 1 , wherein the reservoir trap is configured to cool molecules as they are transported from the reservoir trap to the loading zone of the qubit-array region.
15 . The qubit-array system of claim 1 , wherein the qubit-array is structured so as to define a transport path to the target qubit site.
16 . The qubit-array system of claim 15 , wherein the qubit-array is structured by compressing rows or columns of the qubit-site array.
17 . The qubit-array system of claim 1 , further comprising transmissive materials configured to reduce reflections of light from a reservoir region of the reservoir trap into the qubit-array region.
18 . The qubit-array system of claim 1 , further comprising absorbent materials to absorb light that otherwise could escape a reservoir region of the reservoir trap into the qubit-array region.
19 . 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.
20 . The qubit-array system of claim 1 , wherein the optical tweezers are configured to transport the cold molecule to the target qubit site partially along a plane through all the qubit sites of the qubit-site array.
21 . The qubit-array system of claim 1 , wherein the optical tweezers are configured to transport the cold molecule to the target qubit site partially parallel to a plane through all the qubit sites of the qubit-site array.
22 . The qubit-array system of claim 21 , wherein the optical tweezers are configured to transport the cold molecule to the target qubit site partially orthogonal to the plane through all the qubit sites of the qubit-site array.
23 . A qubit-array loading process comprising:
selecting a target site of a qubit-site array, the qubit-site array being at least partially populated by resident molecules and located within a qubit-array region;
transporting, using a moving standing wave of light, a cold molecule from a reservoir trap located outside the qubit-array region into a loading zone of the qubit-array region; and
transporting, using optical tweezers, the cold molecule from the loading zone of the qubit-array region to the target site of the qubit-site array.
24 . The qubit-array loading process of claim 23 , wherein transporting from the reservoir trap to the qubit-array region is over a distance of at least 2 mm.
25 . The qubit-array loading process of claim 23 , wherein transporting from the reservoir trap to the qubit-array region is over a distance of at least 10 mm.
26 . The qubit-array loading process of claim 25 , wherein the reservoir trap is spaced at most 100 mm from the qubit-array region.
27 . The qubit-array loading process of claim 23 , wherein a target site is vacant for a duration of a transport from within the qubit-array region to the target site.
28 . The qubit-array loading process of claim 23 , 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 qubit-site array.
29 . The qubit-array loading process of claim 23 , wherein transporting of the cold molecule from the reservoir trap to the qubit-array region occurs during storing a value computed by a quantum-logic language in the qubit-site array.
30 . The qubit-array loading process of claim 23 , wherein transporting the cold molecule from the reservoir trap to the loading zone includes manipulating qubit values of molecules located in sections of the qubit-site array not including a target site while a molecule is transported to a target site.
31 . The qubit-array loading process of claim 23 , wherein transporting the cold molecule from the reservoir trap to the loading zone includes using multiple optical tweezers concurrently.
32 . The qubit-array loading process of claim 31 , wherein transporting the cold molecule from the reservoir trap to the loading zone uses the multiple optical tweezers to implement concurrent or pipelined loading of molecules into respective target sites.
33 . The qubit-array loading process of claim 23 , wherein transporting includes loading of a molecule into a target site using a bucket-brigade procedure.
34 . The qubit-array loading process of claim 23 , wherein the reservoir trap is populated with monatomic molecules.
35 . The qubit-array loading process of claim 34 , wherein the monatomic molecules are neutral atoms.
36 . The qubit-array loading process of claim 35 , wherein the neutral atoms are of alkali or alkaline-earth elements.
37 . The qubit-array loading process of claim 23 , wherein transporting the cold molecule from the reservoir trap to the loading zone includes cooling the cold molecule while it is transported from the reservoir trap.
38 . The qubit-array loading process of claim 23 , wherein the qubit-site array is structured so as to define a transport path to the target site.
39 . The qubit-array loading process of claim 38 , wherein the qubit-site array is structured by compressing rows or columns of the qubit-site array.
40 . The qubit-array loading process of claim 23 , further comprising transmitting light through transmissive materials to reduce reflections of light from a reservoir region of the reservoir trap into the qubit-array region.
41 . The qubit-array loading process of claim 23 , further comprising absorbing, by absorbent materials, light that otherwise could escape a reservoir region of the reservoir trap into the qubit-array region.
42 . The qubit-array loading process of claim 23 , further comprising mitigating gas using pumps on either side of a pressure-differential aperture between the reservoir trap and the qubit-array region.
43 . The qubit-array loading process of claim 23 , comprising transporting the cold molecule from the reservoir trap to the loading zone using optical tweezers, crossed acousto-optic deflectors, multi-channel acousto-optic deflectors, spatial-light modulators, electro-optic modulators or liquid crystal modulators.
44 . The qubit-array loading process of claim 23 , comprising transporting the cold molecule to the target site partially along a plane through all qubit-sites of the qubit-site array.
45 . The qubit-array loading process of claim 23 , comprising transporting the cold molecule to the target site partially parallel to a plane through all qubit sites of the qubit-site array.
46 . The qubit-array loading process of claim 45 , comprising transporting the cold molecule to the target site partially orthogonal to the plane through all qubit sites of the qubit-site array.
47 . The qubit-array loading process of claim 23 , further comprising, during transporting the cold molecule from the reservoir trap to the loading zone, manipulating the resident molecules by performing a gate or readout operation.