Abstract: A shield for a cryogenic chamber and a cryogenic chamber comprising a shield are described. In an example embodiment, a cryogenic chamber comprises an interior housing comprising housing walls that define an action chamber. The action chamber is configured to be cryogenically cooled to an action temperature. The cryogenic chamber further comprises an interior shield at least partially sandwiched within the housing walls. The interior shield is made of a first material that acts as a superconductor at the action temperature.

Abstract: Embodiments relate to initializing and/or performing state preparation for an atomic object. The controller controls first manipulation sources to provide first manipulation signals and second manipulation sources to provide second manipulation signals. The first and second manipulation signals are incident on the atomic object. The atomic object has a nuclear spin greater than one half. A ground state manifold of the atomic object comprises one or more selected ground manifold states and non-selected ground manifold states. The first manipulation signals are configured to drive transitions from the non-selected ground manifold states to one or more pumped manifolds of the atomic object and suppress transitions out of the selected ground manifold states. The second manipulation signals are configured to stimulate the atomic object to decay a pumped manifold into a decayed state, wherein there is a non-zero probability that the decayed state is one of the selected ground manifold states.

Abstract: An experimental payload and cryogenic system are provided. An experimental payload including a cryogenic chamber is provided. The cryogenic chamber includes an action chamber configured to be cryogenically cooled to an action temperature. The cryogenic chamber also includes an inner cooling ring cooled via an internal braiding system. The inner cooling ring is configured to operate at a first temperature. The cryogenic chamber further includes an outer ring in communication with the inner cooling ring. The outer ring is configured to absorb heat from the experimental payload. The outer ring defines a second temperature that is greater than the first temperature. The cryogenic chamber also includes a plurality of legs operably coupled to the cryogenic chamber at a top end of each leg. The legs are characterized by a low thermal conductivity and the experimental payload is configured to be attached to a base of a cryocooler.

Abstract: The present subject matter provides technical solutions for the technical problems facing quantum computing by improving the accuracy and precision of qubit readout. Technical solutions described herein improves the readout fidelity by reducing the ambiguity between the bright and dark states. In an embodiment, this includes transferring the qubit population that is in the dark quantum state to an auxiliary third state. The auxiliary third state remains dark and reduces the mixing between the logical bright and dark states. This process uses multiple laser pulses to ensure high fidelity population transfer, thus preserving the dark nature of the dark state. Improving readout fidelity of 171Yb+ qubits may improve fidelity by an order of magnitude, such as by improving readout fidelity from 99.9% to 99.99%. This improvement in detection fidelity may substantially increase the computational power of a quantum computer.

Abstract: An ion trap apparatus is provided. The ion trap apparatus comprises two or more radio frequency (RF) rails formed with substantially parallel longitudinal axes and with substantially coplanar upper surfaces; and two or more sequences of trapping and/or transport (TT) electrodes with each sequence formed to extend substantially parallel to the substantially parallel longitudinal axes of the RF rails. The two or more RF rails and the two or more sequences of TT electrodes define an ion trap. The two or more sequences of TT electrodes are arranged into a number of zones. Each zone comprises wide matched groups of TT electrodes and at least one narrow matched group of TT electrodes. A wide TT electrode is longer and/or wider in a direction substantially parallel to the substantially parallel longitudinal axes of the RF rails than a narrow TT electrode.

Abstract: A cooled system includes an enclosure having an outer surface and an inner surface comprising a cooled enclosed area, multiple cable brackets thermally coupled to the outer surface of the enclosure, each cable bracket including a first surface conforming to the outer surface of the enclosure and an opening therethrough sized to hold a cable and conduct heat from the cable to the outer surface of the enclosure.

Abstract: A quantum computer controller receives a quantum circuit comprising circuit slices. The first slice comprises a past causal cone of a first system qubit wire at a fully evolved level of the circuit. An i-th slice contains all gates that are within a past causal cone of a system qubit wire that reaches the fully evolved level in slice i that are not in the past causal cone of a system qubit wire that reaches the fully evolved level in slice i?j. The controller causes execution of the i-th slice using the physical qubits; causes a physical qubit that was evolved along a system qubit wire to the fully evolved level via execution of the i-th slice to be reinitialized and reintroduced onto a system qubit wire at a base level of the i+m-th slice; and causes the quantum computer to use the physical qubit to execute the i+m-th slice.

Abstract: One or more embodiments are directed to establishing electrical connections through silicon wafers with low resistance and high density, while at the same time maintaining processability for further fabrication. Such connections through silicon wafers enable low resistance connections from the top side of a silicon wafer to the bottom side of the silicon wafer.