Quantum Bloom Filter and Its Applications

A quantum Bloom filter is a spatially more efficient data structure which is used to represent a set of n elements by using O(lognk) qubits. In this article, we define and design a quantum Bloom filter and its corresponding algorithms. Due to the reversibility of quantum operators, it can not only add a new element to a quantum Bloom […]

An Engineer’s Brief Introduction to Microwave Quantum Optics and a Single-Port State-Space Representation

Classical microwave circuit theory is incapable of representing some phenomena at the quantum level. To include quantum statistical effects, various theoretical treatments can be employed. Quantum input-output network (QION) theory is one such treatment. Another formalism, called SLH theory, incorporates scattering matrices ( S ), coupling vectors ( L ), and system Hamiltonians ( H […]

Compiler Design for Distributed Quantum Computing

In distributed quantum computing architectures, with the network and communications functionalities provided by the Quantum Internet, remote quantum processing units can communicate and cooperate for executing computational tasks that single, noisy, intermediate-scale quantum devices cannot handle by themselves. To this aim, distributed quantum computing requires a new generation of quantum compilers, for mapping any quantum […]

Encoding of Nonbinary Entanglement-Unassisted and Assisted Stabilizer Codes

Quantum coding schemes over qudits using preshared entanglement between the encoder and decoder can provide better error correction capability than without it. In this article, we develop procedures for constructing encoding operators for entanglement-unassisted and entanglement-assisted qudit stabilizer codes over Fpk, with p prime and k≥1 from first principles, generalizing prior works on qubit-based codes and codes that work […]

Benchmarking Hamiltonian Noise in the D-Wave Quantum Annealer

Various sources of noise limit the performance of quantum computers by altering qubit states in an uncontrolled manner throughout computations and reducing their coherence time. In quantum annealers, this noise introduces additional fluctuations to the parameters defining the original problem Hamiltonian, such that they find the ground states of problems perturbed from those originally programmed. […]

Formulating and Solving Routing Problems on Quantum Computers

The determination of vehicle routes fulfilling connectivity, time, and operational constraints is a well-studied combinatorial optimization problem. The NP-hard complexity of vehicle routing problems has fostered the adoption of tailored exact approaches, matheuristics, and metaheuristics on classical computing devices. The ongoing evolution of quantum computing hardware and the recent advances of quantum algorithms (i.e., VQE, […]

Josephson Microwave Sources Applied to Quantum Information Systems

Quantum computers with thousands or millions of qubits will require a scalable solution for qubit control and readout electronics. Colocating these electronics at millikelvin temperatures has been proposed and demonstrated, but there exist significant challenges with power dissipation, reproducibility, fidelity, and scalability. In this article, we experimentally demonstrate the use of a Josephson arbitrary waveform […]

Finding Small and Large k-Clique Instances on a Quantum Computer

Algorithms for triangle finding, the smallest nontrivial instance of the k -clique problem, have been proposed for quantum computers. Still, those algorithms assume the use of fixed access time quantum RAM. In this article, we present a practical gate-based approach to both the triangle-finding problem and its NP-hard k -clique generalization. We examine both constant factors for near-term implementation […]

Protocols for Creating and Distilling Multipartite GHZ States With Bell Pairs

The distribution of high-quality Greenberger-Horne-Zeilinger (GHZ) states is at the heart of many quantum communication tasks, ranging from extending the baseline of telescopes to secret sharing. They also play an important role in error-correction architectures for distributed quantum computation, where Bell pairs can be leveraged to create an entangled network of quantum computers. We investigate […]

High-Fidelity Control of Superconducting Qubits Using Direct Microwave Synthesis in Higher Nyquist Zones

Control electronics for superconducting quantum processors have strict requirements for accurate command of the sensitive quantum states of their qubits. Hinging on the purity of ultra-phase-stable oscillators to upconvert very-low-noise baseband pulses, conventional control systems can become prohibitively complex and expensive when scaling to larger quantum devices, especially as high sampling rates become desirable for […]