Embodiments disclosed herein include a resonator for use in quantum computing. The resonator can include a housing that is disposed along a resonator axis. The housing can have a first portion extending from a housing distal end to near a qubit location and a second portion extending from near the qubit location to a housing proximal end. The housing can define a cavity extending from a cavity proximal end to a cavity distal end along a portion of the resonator axis. The housing can include a protrusion extending axially from the housing distal end along the resonator axis to near the qubit location. A proximal portion of the protrusion can include a tapered portion. The resonator can include a qubit extending into the cavity at the qubit location.
Embodiments disclosed herein include a resonator for use in quantum computing. The resonator can include a housing that is disposed along a resonator axis. The housing can have a first portion extending from a housing distal end to near a qubit location and a second portion extending from near the qubit location to a housing proximal end. The housing can define a cavity extending from a cavity proximal end to a cavity distal end along a portion of the resonator axis. The housing can include a protrusion extending axially from the housing distal end along the resonator axis to near the qubit location. A proximal portion of the protrusion can include a tapered portion. The resonator can include a qubit extending into the cavity at the qubit location.
A qubit device for use in a quantum computing environment includes a semiconductor substrate, an insulating layer disposed on at least a portion of an upper surface of the substrate, and a transition metal silicide (TMSi) heterojunction disposed on at least a portion of an upper surface of the insulating layer. The TMSi heterojunction includes a link layer and at least first and second TMSi regions coupled with the link layer. The link layer may include a normal conductor, thereby forming a superconductor-normal conductor-superconductor (SNS) junction, or a geometric constriction, thereby forming a superconductor-geometric constriction-superconductor (ScS) junction. The link layer may form at least a portion of a channel including intrinsic or doped silicon.
An apparatus for performing quantum computing includes multiple qubits, each of at least a subset of the qubits comprising a loop formed of a Dirac or Weyl semimetal and having at least two stable quantum states. The apparatus further includes at least one terahertz cavity coupled with the qubits, the terahertz cavity being configured to detect the quantum states of the qubits. Each of at least the subset of qubits is configured to receive a circularly polarized radiation source. The radiation source is adapted to excite a chiral current in each of at least the subset of qubits, the quantum states of the plurality of qubits being a function of the chiral current.
A quantum computing system includes a quantum processor having a plurality of qubits, a classical memory, and a classical processor. The classical processor is configured to compile a quantum program into logical assembly instructions in an intermediate language, aggregate the logical assembly instructions together into a plurality of logical blocks of instructions, generate a logical schedule for the quantum program based on commutativity between the plurality of logical blocks, generate a tentative physical schedule based on the logical schedule, the tentative physical schedule includes a mapping of the logical assembly instructions in the logical schedule onto the plurality of qubits of the quantum processor, aggregate instructions together within the tentative physical schedule that do not reduce parallelism, thereby generating an updated physical schedule; generate optimized control pulses for the aggregated instructions, and execute the quantum program on the quantum processor with the optimized control pulses and the updated physical schedule.
Abstract Quantum computers (QC), if realized, could disrupt many computationally intense fields of science. The building block element of a QC is a quantum bit (qubit). Qubits enable the use of quantum superposition and multi-state entanglement in QC calculations, allowing a QC to simultaneously perform millions of computations at once. However, quantum states stored in a qubit degrade with decreased quality factors and interactions with the environment. One technical solution to improve qubit lifetimes and network interactions is a circuit comprised of a Josephson junction-based qubit located inside of a high Q-factor superconducting 3D cavity. It is known that niobium resonators can reach Q0>1011 Q0>1011 . However, existing cavity geometries are optimized for particle acceleration rather than hosting qubits. RadiaBeam Technologies, in collaboration with Argonne National Laboratory and The University of Chicago, has developed a niobium superconducting radio frequency quarter-wave resonant cavity (QWR) for quantum computation. A 6 GHz QWR was optimized to include tapering of the inner and outer conductors, a toroidal shape for the resonator shorting plane, and an inner conductor tip to reduce parasitic capacitance. In this paper, we present the results of the resonator design optimization, fabrication, processing, and testing.
A quantum computing system includes a quantum processor having a plurality of qubits, a classical memory, and a classical processor. The classical processor is configured to compile a quantum program into logical assembly instructions in an intermediate language, aggregate the logical assembly instructions together into a plurality of logical blocks of instructions, generate a logical schedule for the quantum program based on commutativity between the plurality of logical blocks, generate a tentative physical schedule based on the logical schedule, the tentative physical schedule includes a mapping of the logical assembly instructions in the logical schedule onto the plurality of qubits of the quantum processor, aggregate instructions together within the tentative physical schedule that do not reduce parallelism, thereby generating an updated physical schedule; generate optimized control pulses for the aggregated instructions, and execute the quantum program on the quantum processor with the optimized control pulses and the updated physical schedule.
We initiate the systematic study of QMA algorithms in the setting of property testing, to which we refer as QMA proofs of proximity (QMAPs). These are quantum query algorithms that receive explicit access to a sublinear-size untrusted proof and are required to accept inputs having a property Π and reject inputs that are ε -far from Π , while only probing a minuscule portion of their input.We investigate the complexity landscape of this model, showing that QMAPs can be exponentially stronger than both classical proofs of proximity and quantum testers. To this end, we extend the methodology of Blais, Brody, and Matulef (Computational Complexity, 2012) to prove quantum property testing lower bounds via reductions from communication complexity. This also resolves a question raised in 2013 by Montanaro and de Wolf (cf. Theory of Computing, 2016).Our algorithmic results include a purpose an algorithmic framework that enables quantum speedups for testing an expressive class of properties, namely, those that are succinctly decomposable . A consequence of this framework is a QMA algorithm to verify the Parity of an n -bit string with O(n2/3) queries and proof length. We also propose a QMA algorithm for testing graph bipartitneness, a property that lies outside of this family, for which there is a quantum speedup.