Search

Ramsey interferometers are used as a general tool of spectroscopy and matter wave interferometry. The authors demonstrate an echo- Ramsey interferometer that uses trapped quantum states in an optical lattice as a new tool to study coherence in many body quantum systems.

Reducing rotational dephasing is a major challenge in ultracold molecules. Here, the authors demonstrate coherent control of three rotational states in ultracold molecules trapped in magic-wavelength optical tweezers, opening prospects towards quantum applications with higher-dimensional systems.

Ionizing radiation can cause simultaneous charge noise in multi-qubit superconducting devices. Here, the authors measure space- and time-correlated charge jumps in a four-qubit system in a low-radiation underground facility, achieving operation with minimal correlated events over 22 h at qubit separations beyond 3 mm.

Coherence between rotational states of polar molecules has previously been limited by light shifts in optical traps. A magic-wavelength trap is able to maximize the coherence time and enables the observation of tunable dipolar interactions.

A quantum simulation of a (2 + 1)-dimensional lattice gauge theory is carried out on a quantum computer working with neutral atoms trapped by optical tweezers in a Kagome geometry.

Compact atomic clocks and atom interferometers are desired for on-chip integration. Here the authors demonstrate a chip-scale atomic beam of 87Rb atoms and its application as an atomic beam clock

A new approach to generating quantum sensors with close-to-optimal performance is demonstrated experimentally through Ramsey interferometry with (up to) N = 26 entangled atoms on a trapped-ion quantum computer, without a priori knowledge of the device or its noise environment.

The hyperfine states of ultracold polar molecules are a strong candidate for storing quantum information. Identifying and eliminating all detectable causes of decoherence has extended the qubit coherence time beyond 5.6 s in RbCs molecules.

Decoherence is anathema to quantum systems, as it reduces their performance and stability. Shulman et al.show that real-time Hamiltonian parameter estimation can significantly increase the coherence time of a qubit by enabling continuous adjustment of its control parameters.

Spin–photon interfaces provide a connection between quantum information stored in atomic or electronic spins and optical communications networks. A quantum photon emitter with long-lived, controllable coherent spin has now been demonstrated.

Two-dimensional arrays of trapped ion qubits are attractive platforms for quantum information processing, but rapid reloading remains a challenge. Here the authors use a continuous flux of pre-cooled neutral atoms to achieve fast loading of single ions without affecting the coherence of adjacent qubits.

A nitrogen impurity in diamond—where two of the carbon atoms are replaced by a nitrogen atom and a vacant lattice site—is seen as a valuable qubit. The spin of an electron localized to the nitrogen-vacancy centre is commonly used for processing. Researchers now show that this electron spin state can be transferred to the nitrogen nuclear spin, where it can be stored until needed.

Using ultracold atoms in hybrid quantum devices is an interesting yet challenging task with possible applications for quantum storage. Here the authors demonstrate coherent magnetic coupling of an ensemble of ultracold rubidium atoms to a superconducting coplanar waveguide resonator.

The presence of various noises in the qubit environment is a major limitation on qubit coherence time. Here, the authors demonstrate the use a closed-loop feedback to stabilize frequency noise in a flux-tunable superconducting qubit and suggest this as a scalable approach applicable to other types of noise.

Solid-state systems are established candidates to study models of many-body physics but have limited control and readout capabilities. Ensembles of defects in diamond may provide a solution for studying dipolar systems.

Ramsey interferometers are used to measure minute energy shifts, but they are usually only applied to simple, non-interacting ensembles. Here, the authors demonstrate a two-pulse Ramsey-type interferometer built on the motional states of an interacting Bose–Einstein condensate using optimal control.

Alkene-terminated silicon carbide surfaces are proposed as a room-temperature divacancy spin qubit quantum sensor suitable for bioimaging and nanoscale nuclear spin sensing.

Researchers demonstrate fast, single-qubit gates using a sequence of 13 ps pulses. Two vertically stacked InAs/GaAs quantum dots were coupled through coherent tunnelling and charged with controlled numbers of holes. The interaction between hole spins was investigated by Ramsey fringe experiments, showing a tunable interaction range of tens of gigahertz.

Many-body effects in an interacting spin-orbit coupled Fermi gas are studied with the help of clock spectroscopy. The results provide a simple view of how strong collective dynamics arise from local interactions in the presence of spin–orbit coupling.

A quantum computer requires quantum systems that are well-isolated from external perturbations, but which can still be easily manipulated with external fields. A scheme that uses spatially inhomogeneous fields to selectively address neutral-atom qubits while they are in field-insensitive superposition states satisfies these competing needs.

Two-qubit operations exceeding 99% fidelity have been demonstrated by silicon devices made with standard semiconductor tooling in a 300-mm foundry environment.

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.

We present atom interferometry performed in a laboratory-scale Einstein Elevator over several days with high reproducibility. This table-top experiment enables long-term metrological assessments of quantum inertial sensors in microgravity.

Shallow NV centers in diamond are advantageous for quantum sensing but suffer from surface magnetic noise. Using first-principles simulations supported by experiments, the authors show that a combination of small magnetic fields and surface strain can significantly enhance spin coherence of 1 nm-deep NV centers.

Cold-atom interferometers have been miniaturized towards fieldable quantum inertial sensing applications. Here the authors demonstrate a compact cold-atom interferometer using microfabricated gratings and discuss the possible use of photonic integrated circuits for laser systems.

Trapped ion quantum systems based on sympathetic cooling use ions of different species. Here the authors demonstrate exchange cooling using two ions of the same species (⁴⁰Ca⁺) by taking advantage of the exchange of energy when the ions are brought close together.

An elementary quantum network of two entangled atomic clocks is demonstrated; the high fidelity and speed of entanglement generation show that entangled clocks can offer practical enhancement for metrology.

Quantum magnetometry in the solid state is usually affected by short coherence times and control errors that limit the sensitivity. This work demonstrates a continuous-driving scheme based on composite pulses that improves both these shortcomings and can be used in variable sensing environments.

Superconducting circuits are promising for quantum computing, but quasiparticle tunnelling across Josephson junctions introduces qubit decoherence. Ristè et al. convert a transmon qubit into its own real-time quasiparticle tunnelling detector and accurately measure induced decoherence in the millisecond range.

The authors fabricate a fluxonium circuit using a granular aluminium nanoconstriction to replace the conventional superconductor–insulator–superconductor tunnel junction. Their characterization suggests that this approach will be a useful element in the superconducting qubit toolkit.

Silicon is a promising material for realization of quantum processors, particularly as it could be naturally integrated with classical control hardware based on CMOS technology. Here the authors report a silicon qubit device made with an industry-standard fabrication process on a CMOS platform.

Superconducting qubits are highly sensitive to magnetic fields, limiting their integration with spin-based quantum systems. Here, the authors demonstrate a superconducting qubit that maintains coherence beyond 1T, revealing spin-1/2 impurities and magnetic freezing of flux noise.

Cosmic-ray particles and γ-rays striking superconducting circuits can generate qubit errors that are spatially correlated across several millimetres, hampering current error-correction approaches.

Electron spin in quantum dots are extensively studied as a qubit for quantum information processing. However, the coherence of electron spin is deleteriously influenced by nuclear spin. Quantum-dot holes are a potential alternative. Full control over hole-spin qubits is now achieved using picosecond lasers.

Quantum communication networks would greatly benefit from the possibility to have solid-state emitters being directly interfaced with telecom fibers, without the need for wavelength conversion. Here, the authors demonstrate coherent control of an InAs/InP quantum dot, as well as entanglement between its electron spin and the frequency of a telecom photon.

The authors report an experiment demonstrating fast control of the quantum dot–cavity coupling, indicating the coherent transfer of photons between the cavity and the quantum dot.

Quantum sensing based on solid-state spins can be improved with the use of adaptive strategies.

Quantum annealers hold promise of outperforming classical computers in solving hard optimization problems, but one main challenge is understanding the role of noise in quantum annealing. Here, the authors characterize the relevant noise sources in a tunable flux qubit, a building block for quantum annealers, and provide a benchmark for future work on highly-coherent quantum annealers.

A chip-integrated laser with 7.5 × 10⁻¹⁴ fractional frequency instability is demonstrated by active stabilization to an on-chip 6.1-m-long spiral resonator. By using this laser to interrogate the narrow-linewidth transition of ⁸⁸Sr⁺, a clock instability averaging down as \(3.9\times 1{0}^{-14}/\sqrt{\tau }\) is achieved.

Gatemons, or gate-tunable transmons, are superconducting qubits based on hybrid Josephson junctions, which typically use extended quantum conductors as weak links. Here the authors report a gatemon made with a carbon-nanotube-based junction, showing improved coherence time compared to graphene-based devices.

Interspecies comparisons between atomic optical clocks are important for several technological applications. A recently proposed spectroscopy technique extends the interrogation times of clocks, leading to highly stable comparison between species.

Optical clocks with a record low zero-dead-time instability of 6 × 10^–17 at 1 second are demonstrated in two cold-ytterbium systems. The two systems are interrogated by a shared optical local oscillator to nearly eliminate the Dick effect.

Carbon nanotubes are promising hosts for spin qubits, however existing demonstrations show limited coherence times. Here the authors report quantum states in a carbon-nanotube-based circuit driven solely by cavity photons and exhibiting a coherence time of about 1.3 μs.

Despite recent advances with trappedion-based platforms, achieving quantum networks with link efficiency greater than unity on metropolitan scales is still a challenge. Here, the authors demonstrate a multiplexed quantum network generating heralded entanglement at a rate faster than local decoherence.

Coherent manipulation of hole-orbital states in semiconductor quantum dots is achieved through stimulated Auger processes, opening doors to new types of orbital-based solid-state quantum photonic devices.

Er³⁺ is implanted into CaWO₄, a material with non-polar site symmetry free of background rare earth ions, to realize reduced optical spectral diffusion in nanophotonic devices, representing a step towards making telecom band quantum repeater networks with single ions.

An exhausting characterization of the coherence properties of quantum system becomes challenging with increasing system size. Here the authors demonstrate that phonon autocorrelation functions and quantum discord can be measured with local control, and validate it in a string of 42 trapped ions.

A graphene-based Josephson junction incorporated in a superconducting circuit forms a voltage-tunable transmon qubit that can be controlled coherently.