Researchers in quantum technology at Chalmers University of Technology have succeeded in developing a technique to control quantum states of light in a three-dimensional cavity. In addition to creating previously known states, the researchers are the first ever to demonstrate the long-sought cubic phase state. The breakthrough is an important step towards efficient error correction in quantum computers.

Quantum technology reaches unprecedented control over captured light

Researchers in quantum technology have succeeded in developing a technique to control quantum states of light in a three-dimensional cavity. In addition to creating previously known states, the researchers are the first ever to demonstrate the long-sought cubic phase state. The breakthrough is an important step towards efficient error correction in quantum computers.

Upgrading your computer to quantum

Researchers have demonstrated how a nanoscale layer of superconducting niobium nitride (NbNx) can be grown directly onto aluminum nitride (AIN). The arrangement of atoms, nitrogen content, and electrical conductivity were found to depend on growth […]

Key element for a scalable quantum computer

Millions of quantum bits are required for quantum computers to prove useful in practical applications. But this is still a long way off. One problem is that the qubits have to be very close to […]

Quantum error mitigation.

Quantum Error Mitigation: Confronting Fundamental Limits

Researchers have established fundamental theoretical bounds on quantum error mitigation techniques, proving that certain performance limitations are unavoidable physics constraints rather than technological shortcomings, with sampling overhead scaling exponentially with circuit depth for local depolarizing noise and confirming the optimality of probabilistic error cancellation for mitigating local dephasing noise.

Silicon nanopillars for quantum communication

Across the world, specialists are working on implementing quantum information technologies. One important path involves light: Looking ahead, single light packages, also known as light quanta or photons, could transmit data that is both coded […]

Scheme of constructing three-qubit quantum logic gates.

Quantum Fredkin and Toffoli gates on a versatile programmable silicon photonic chip

This research demonstrates a groundbreaking implementation of three-qubit Fredkin and Toffoli gates on a programmable quantum photonic chip, overcoming previous limitations of pre-entangled input states and bulk optics systems by using controlled Mach-Zehnder interferometers to enable independent input photons, marking a significant advance toward scalable quantum processors.

The lattice representations of (rotated) surface and toric codes.

Memory-Enhanced Belief Propagation for Quantum Error Correction

The researchers developed MBP (Memory-effect Belief Propagation), an enhanced version of traditional belief propagation that incorporates memory effects and neural network-like inhibition functionality, enabling efficient decoding of highly degenerate quantum error-correcting codes with significantly improved performance, achieving error thresholds of 16% and 17.5% for surface and toric codes respectively.

Topological nonlinear optics with spin-orbit coupled Bose-Einstein condensate in cavity

Topological Light: Spin-Orbit BECs Create Quantum Gateways

Researchers theoretically demonstrate how spin-orbit coupled Bose-Einstein condensates in optical cavities can generate topological optical transparencies with Dirac cones and edge-like states, potentially advancing quantum computation through enhanced light-matter interactions that exhibit phase transitions controllable via Raman detuning and atomic damping.

Sketch of the open cavity magnonic system.

Cooperative-effect-induced one-way steering in open cavity magnonics

Researchers demonstrated a novel method to generate and control one-way quantum steering between photon and magnon modes in a non-Hermitian cavity magnonic system by leveraging the cooperative effects of coherent and dissipative coupling, achieving robust quantum correlations that can be precisely controlled through the relative phase of cooperative dissipation and magnon mode frequency detuning.

Geometric representation of the principles of nonorthogonal state discrimination.

Experimental investigation of wave-particle duality relations

A groundbreaking experimental study validates both the previously tested quadratic (D2 + V2 ≤ 1) and theoretically predicted linear forms of wave-particle duality relations through asymmetric beam interference and photon polarization measurements, revealing that the quadratic form yields more path information and advancing our understanding of these fundamental quantum principles.

Quantum materials: Entanglement of many atoms discovered

Be it magnets or superconductors: materials are known for their various properties. However, these properties may change spontaneously under extreme conditions. Researchers have discovered an entirely new type of such phase transitions. They display the […]

Device layout and shuttling pulse.

Conveyor-Mode Electron Shuttling Enables Scalable Si/SiGe Quantum Bus

Single-electron conveyor-mode shuttling in Si/SiGe quantum channels demonstrates 99.42% fidelity using only four control signals independent of distance, enabling scalable quantum computing architectures by solving the signal-fanout problem in connecting dense qubit registers.

Entangled photons tailor-made

Physicists have managed to entangle more than a dozen photons efficiently and in a defined way. They are thus creating a basis for a new type of quantum computer. Read More Quantum Computers News — […]

The features of superlattice.

A scheme to create and verify scalable entanglement in optical lattice

The research proposes a novel scheme for generating scalable quantum entanglement using ultracold atoms in optical superlattices, where atoms are sequentially entangled in double wells and then reconfigured through lattice phase shifts, resulting in a noise-resistant genuine multipartite entangled state suitable for practical quantum computing implementations.

Researchers demonstrate error correction in a silicon qubit system

Researchers have achieved a major step toward large-scale quantum computing by demonstrating error correction in a three-qubit silicon-based quantum computing system. This work could pave the way toward the achievement of practical quantum computers. Read […]