Quantum-mechanical effects at the macroscopic level were first explored in Josephson-
junction-based superconducting circuits in the 1980s. In recent decades, the emergence of …

Quantum information processing relies on the precise control of non-classical states in the
presence of many uncontrolled environmental degrees of freedom. The interactions …

Performing large calculations with a quantum computer will likely require a fault-tolerant
architecture based on quantum error-correcting codes. The challenge is to design practical …

We present a comprehensive architectural analysis for a proposed fault-tolerant quantum
computer based on cat codes concatenated with outer quantum error-correcting codes. For …

Since the first observation of coherent quantum behaviour in a superconducting qubit, now
more than 20 years ago, there have been substantial developments in the field of …

Quantum superpositions of macroscopically distinct classical states—so-called Schrödinger
cat states—are a resource for quantum metrology, quantum communication and quantum …

While quantum computers promise to solve some scientifically and commercially valuable
problems thought intractable for classical machines, delivering on this promise will require a …

Quantum information is vulnerable to environmental noise and experimental imperfections,
hindering the reliability of practical quantum information processors. Therefore, quantum …

Encoding a qubit in logical quantum states with wave functions characterized by disjoint
support and robust energies can offer simultaneous protection against relaxation and pure …

During the last ten years, superconducting circuits have passed from being interesting
physical devices to becoming contenders for near-future useful and scalable quantum …