Search

Quantum computing platforms allowing quantum error correction usually rely on complex redundant encoding within multiple two-level systems. Here, instead, the authors realize a CNOT gate between two qubits encoded in the multiphoton states of two microwave cavities nonlinearly coupled by a transmon.

Fractional Chern insulators, topological insulators with partially filled bands, do not require large magnetic fields to form fractional quantum Hall states. Here, the authors investigate the correlation between the stability of such states and the bandgap to their creation on a variety of lattices.

People living in rural areas of the United States have poorer outcomes from acute COVID-19. Here, the authors show that higher mortality rates among rural dwellers persist for up to two years after the initial infection, even after accounting for baseline risk factors.

Optomechanical systems are typically modelled as a single cavity mode coupled to a mechanical oscillator. Here, the authors report on the realization of a multimode optomechanical setup whose distinct features arise from the mechanically induced coupling between the cavity modes.

SARS-CoV-2 vaccines containing Omicron subvariant XBB 1.5 were introduced in the United States in 2023. Here, the authors assess the safety of these vaccines by analysing the occurrence of 15 adverse events of special interest following vaccine receipt using electronic health record data.

One of the advantages that it is hoped quantum computers will have over classical computers is their ability to accurately simulate quantum phenomena. Silveri et al.take a step towards this goal by simulating so-called motional averaging in an artificial atom realized by a superconducting quantum bit.

The emerging field of circuit quantum electrodynamics could pave the way for the design of practical quantum computers.

Quantum error correction of Gottesman–Kitaev–Preskill code states is realized experimentally in a superconducting quantum device.

A report on an improved design of an optomechanical system in which a movable membrane is placed between two rigid high-quality mirrors, as opposed to previous designs where one of the mirrors has a double function as the microresonator; it's claimed that it is feasible to reach the quantum-limited ground state with this new design.

Dual-rail encodings of quantum information can be used to detect loss errors, allowing these errors to be treated as erasures. The measurement of dual-rail states with error detection has now been demonstrated in superconducting cavities.

Quantum non-demolition (QND) measurements interrogate a quantum state without disturbing it. A QND scheme that uses a superconducting circuit to investigate microwave photons trapped in a cavity is now shown. The measurement answers the question: are there exactly N photons in the cavity?

A study demonstrates the extension of a lifetime of a quantum memory using active quantum error correction and reinforcement learning.

A quantum-error-correction system is demonstrated in which natural errors due to energy loss are suppressed by encoding a logical state as a superposition of Schrödinger-cat states, which results in the system reaching the ‘break-even’ point, at which the lifetime of a qubit exceeds the lifetime of the constituents of the system.

A controlled-controlled NOT, or Toffoli, gate is used to develop a fast, high-fidelity, three-qubit error correction protocol with the potential to correct arbitrary single-qubit errors.

Repeated error correction creates a logical qubit encoded in the hybrid state of a superconducting circuit and a bosonic cavity, which is shown to be fully controllable under a universal single-qubit gate set.

An artificial Kerr medium has been engineered using superconducting circuits, enabling the observation of the characteristic collapse and revival of a coherent state; this behaviour could, for example, be used in single-photon generation and quantum logic operations.

Quantum computers, which harness the superposition and entanglement of physical states, hold great promise for the future. Here, the demonstration of a two-qubit superconducting processor and the implementation of quantum algorithms, represents an important step in quantum computing.

A noise-resilient protocol implemented in a cavity resonator coupled to a qubit demonstrates that large nonlinear couplings are not a necessary requirement for the fast universal control and state preparation of engineered quantum systems.

Quantum entanglement is a key resource for technologies such as quantum communication and computation. A major question for solid-state quantum information processing is whether an engineered system can display the three-qubit entanglement necessary for quantum error correction. A positive answer to this question is now provided. A circuit quantum electrodynamics device has been used to demonstrate deterministic production of three-qubit entangled states and the first step of basic quantum error correction.

The exploration of the Jaynes–Cummings Hamiltonian in a circuit-QED system—where an ‘artificial atom’ made of a superconducting circuit is strongly coupled to a microwave field—provides direct evidence for nonlinearities due to quantum mechanics on the level of single atoms and photons.

A special version of a cavity quantum electrodynamics system, namely one that is embedded within an electronic circuit has been constructed. A superconducting quantum bit interacts with photons from a microwave transmission line. A novel regime can be obtained with this system, namely the strong dispersive limit, where a single photon has a large effect on the qubit without ever being absorbed.

One of two papers that demonstrate the communication of individual quantum states between superconducting qubits via a quantum bus. This quantum bus is a resonant cavity formed by a superconducting transmission line of several millimetres. Quantum information, initially defined in one qubit on one end, can be stored in this quantum bus and at a later time retrieved by a second qubit at the other end.

A qubit generated and stabilized in a superconducting microwave resonator by encoding it into Schrödinger cat states produced by Kerr nonlinearity and single-mode squeezing shows intrinsic robustness to phase-flip errors.

The minimum noise energy that a phase-preserving amplifier adds to the signal is fundamentally limited to half a photon. A proposed parametric amplifier based on Josephson junctions should be able to reach this limit at microwave frequencies.

An on-chip, on-demand efficient source of single microwave photons that can be used for processing quantum information in a circuit of superconducting qubits is demonstrated. The single photon source is an important addition to a rapidly growing toolbox for quantum optics on a chip.

An entangled Bell state of two superconducting quantum bits can be stabilized for an arbitrary time using an autonomous feedback scheme, that is, one that does not require a complicated external error-correcting feedback loop.

Recent progress in solid-state quantum information processing has stimulated the search for amplifiers and frequency converters with quantum-limited performance in the microwave range. Here, a phase-preserving, superconducting parametric amplifier with ultra-low-noise properties has been experimentally realized.

Two superconducting cavity modes are entangled using an exponential-SWAP logic gate.

Sending quantum states as shaped microwave photonic wavepackets realizes on-demand, high-fidelity quantum state transfer and entanglement between two superconducting cavity quantum memories.

The quantized changes in the photon number parity of a microwave cavity can be tracked on a short enough timescale, and with sufficiently little interference with the quantum state, for this parity observable to be used to monitor the occurrence of error in a recently proposed protected quantum memory.

Experiment overturns Bohr’s view of quantum jumps, demonstrating that they possess a degree of predictability and when completed are continuous, coherent and even deterministic.