Controlling the Waveform of Ultrashort Infrared Pulses

Ultrashort infrared light pulses are the key to a wide range of technological applications. The oscillating infrared light field can excite molecules in a sample to vibrate at specific frequencies, or drive ultrafast electric currents […]

Topological phase detected in spin chains

In a special arrangement of atomic spins, Max Planck physicists have measured the properties of the so-called Haldane phase in an experiment. To do so, they used a quantum mechanical trick. In some materials, there […]

Quantum entanglement can be used as a noise filter for recording speech. Credit: Florian Kaiser

Quantum entanglement as a noise filter for microphone

Engineers are developing commercial microphones focus on eliminating technical sources of noise, such as that found in the signal amplifiers. But even when the technical noise sources are addressed, there is still a fundamental noise stemming […]

The rotating cryostat used for the research - © Aalto University/Mikko Raskinen

Time crystals ‘impossible’ but obey quantum physics

A time crystal is a macroscopic quantum system in periodic motion in its ground state. In our experiments, two coupled time crystals consisting of spin-wave quasiparticles (magnons) form a macroscopic two-level system. The two levels evolve in time as determined intrinsically by a nonlinear feedback, allowing us to construct spontaneous two-level dynamics. In the course of a level crossing, magnons move from the ground level to the excited level driven by the Landau-Zener effect, combined with Rabi population oscillations. We demonstrate that magnon time crystals allow access to every aspect and detail of quantum-coherent interactions in a single run of the experiment. Our work opens an outlook for the detection of surface-bound Majorana fermions in the underlying superfluid system, and invites technological exploitation of coherent magnon phenomena – potentially even at room temperature.

Artist impression of gate operations on logical quantum bits, that are protected from faults by means of quantum error correction.

Toward error-free quantum computing

A team of experimental physicists, at the University of Innsbruck, Austria, has implemented a universal set of computational operations on fault-tolerant quantum bits for the first time, demonstrating how an algorithm can be programmed on […]

The semiconductor nanosheets in the water-cooled copper mount turn an infrared laser pulse into an effectively unipolar terahertz pulse. The team says that their terahertz emitter could be made to fit inside a matchbox. Credit: Christian Meineke, Huber Lab, University of Regensburg

Emulating impossible ‘unipolar’ laser pulses

A laser pulse that sidesteps the inherent symmetry of light waves could manipulate quantum information, potentially bringing us closer to room temperature quantum computing. While laser pulses can be used to manipulate the energy states […]

Example of a LASIQ anneal process. Credit: Science Advances (2022). DOI: 10.1126/sciadv.abi6690

Laser annealing transmon qubits 

A team of scientists at IBM Quantum used laser annealing to selectively tune transmon qubits into the desired frequency patterns. Superconducting quantum processors with more than 50 qubits are currently actively available and these fixed […]

When quan­tum par­ti­cles fly like bees

When quan­tum par­ti­cles fly like bees

At first glance, a system consisting of 51 ions may appear simple. But even if these charged atoms can only assume two different states, there will be more than two quadrillion (1015) different configurations which the system can […]

Quantum circuits to implement the measurement bases.

Scalable estimation of pure multi-qubit states

Researchers have introduced an inductive n-qubit pure-state estimation method based on projective measurements on mn + 1 separable bases or m entangled bases plus the computational basis, with m ≥ 2. The method exhibits a favorable scaling in the number of qubits compared to […]

More efficiency for optical quantum gates

Researchers at the Max Planck Institute of Quantum Optics succeeded in massively improving the performance of a component that is crucial to optical quantum systems. Future quantum computers are expected not only to solve particularly […]

The lab S18 at the Institut Laue Langevin (ILL) in Grenoble

New quantum superposition measurement

A new two-path-interference experiment has been designed at TU Wien that only has to measure one specific particle to prove quantum superposition. A single neutron is measured at a specific position — and due to […]

A 3D representation of the spin-excitation continuum -- a possible hallmark of a quantum spin liquid -- observed in 2019 in a single crystal sample of cerium zirconium pyrochlore. (Image by Tong Chen/Rice University)

Computational sleuthing confirms first 3D quantum spin liquid

Computational detective work by physicists has confirmed cerium zirconium pyrochlore is a 3D quantum spin liquid, a solid material in which quantum entanglement and the geometric arrangement of atoms cause electrons to fluctuate between quantum […]

The VED framework for detecting entanglement on near-term quantum devices.

Detecting and quantifying entanglement on NISQ devices

Quantum entanglement is a key resource in quantum technology, and its quantification is a vital task in the current noisy intermediate-scale quantum (NISQ) era. Researchers have combined hybrid quantum-classical computation and quasi-probability decomposition to propose […]

Harvard, QuEra Computing observe quantum speed-up in optimization problems

Quantum speed-up in optimization problems using Rydberg atoms

A collaboration between Harvard University with scientists at QuEra Computing, MIT, University of Innsbruck and other institutions has demonstrated a breakthrough application of neutral-atom quantum processors to solve problems of practical use. Previously, neutral-atom quantum […]