Search

A general approach to simplifying quantum logic circuits—the ‘programs’ of quantum computers—is described and demonstrated on a platform based on photonic qubits.

A superconducting quantum computer is used to realize an out-of-equilibrium topologically ordered state, which hosts anyonic excitations.

Parity-time symmetry breaking and related non-Hermitian phenomena, such as high-order exceptional points, have attracted significant interest across various experimental platforms. Here the authors demonstrate a third-order exceptional point induced by parity-time symmetry breaking in a dissipative trapped ion.

Quantum theory has been shown to be compatible with processes violating a definite causal order, but no detailed analysis of the maximum allowed degree of violation has been carried out so far. Here, the authors fill this gap by providing the analogue of Tsirelson’s bound for the violation of causal inequalities.

Quantum theory can describe scenarios with an indefinite causal order, but whether such processes could be witnessed in real scenarios by violating causal inequalities is still subject to debate. Here, the authors give an affirmative answer, showing that noncausal processes admit a description using the framework of time-delocalised subsystems.

Assuming that all physical systems are ultimately quantum, it is natural to ask how the world “looks like” from the perspective of a quantum reference frame (QRF). Starting from a general notion of symmetry, the authors develop a complete theory for “jumping” between different QRFs, and uncover previously unnoticed degrees of freedom, which are essential for a complete quantum description.

While unusual processes allowing indefinite causal order are gaining attention in quantum physics, formalisms describing definite causal structures have so far been limited to acyclic ones. Here the authors extend to the cyclic case, offering a causal perspective on causally indefinite processes.

A Bell-like experiment that discriminates between real-number and complex-number multipartite quantum systems could disprove real quantum theory.

Open quantum systems are subject to dephasing that ultimately destroys the information they hold. Here, the authors use a superconducting qubit to show that dephasing also has a geometric origin, which can either reduce or restore coherence depending on the path of the quantum system in its Hilbert space.

The mathematical structure of quantum measurements and the Born rule are usually imposed as axioms; here, the authors show instead that they are the only possible measurement postulates, if we require that arbitrary partitioning of systems does not change the theory’s predictions.

An in vitro system that recapitulates temporal characteristics of embryonic development demonstrates that the different rates of mouse and human embryonic development stem from differences in metabolic rates and—further downstream—the global rate of protein synthesis.

Aberrant synchronous oscillations have been associated with numerous brain disorders, including essential tremor. The authors show that synchronous cerebellar activity can casually affect essential tremor and that its underlying mechanism may be related to the temporal coherence of the tremulous movement.

Using a virtual reality apparatus in rats that dissociates external landmarks from self-motion cues, the authors describe how the two modes of theta phase coding in the hippocampus during navigation are controlled via distinct computations.

Quantum trajectory frameworks describe systems weakly coupled to their environment. Here, by including an extra 1D variable in the dynamics, the authors introduce a quantum trajectory framework for time local master equations derived at strong coupling while keeping the computational complexity under control.

The authors use laser imaging techniques to capture wind dynamics over the ocean. The fine-scale structure of the airflow within the first centimeters above waves reveals the coexistence of different wind-wave coupling mechanisms.

Artificial gauge fields unlock additional degrees of freedom to manipulating light in structured photonic systems. This Review strives to unify topological, non-Abelian and non-Hermitian photonics using the concept of gauge fields.

Recent photo-emission experiments reported a strong nearest-neighbour attraction in a 1D cuprate, possibly originating from long-range electron-phonon coupling. By using state-of-the-art numerical methods, the authors show that a Hubbard model with extended electron-phonon terms reproduces experimental features.

The brain and body are necessarily connected. Here the authors show that brain blood flow and electrical activity are coupled with systemic physiological changes in the body.

Light can control neural activity but often requires genetic modification. Here, the authors present a graphene-based platform for non-genetic light controlled neuronal stimulation, enabling all-optical network analysis, stem cell derived neuron maturation, and closed-loop robotics.

Exotic quantum states can be advantageous for sensing, but are very fragile, so that some form of quantum error correction is needed. Here, the authors show how approximate QEC helps overcoming decoherence due to noise when measuring the excitation population of a receiver mode in a superconducting circuit.

Practical implementations of quantum photonic circuits consist primarily of large waveguide networks to path-encode information. Here, Mohantyet al. demonstrate quantum interference between transverse spatial modes in a single silicon nitride waveguide, enabling robust quantum information processing.

How are memories transferred from short-term to long-term storage? Here, the authors show that during deep (NREM) sleep, the prefrontal cortex initiates rapid, bidirectional interactions to trigger information transfer from the hippocampus to the neocortex.

Extending quantum photonics’ capabilities from simple linear-optics-based schemes to universal quantum computing presents several challenges, but intermediate regimes with some degree of adaptivity might already bring practical advantages. Here, the authors experimentally emulate an adaptive Boson Sampling scheme using post-selection, and apply it to a data classification task.

An emergent randomness arising from partial measurement of an interacting many-body system is uncovered, and a widely applicable fidelity estimation scheme is presented that works at shorter evolution times and with reduced experimental complexity.

Arrays of interacting atoms held in optical lattices provide a potentially powerful platform for simulating and studying complex physical phenomena. Tagliacozzo et al. propose a means to explore computationally challenging non-Abelian lattice gauge theories in a lattice of Rydberg atoms.

The light patterns in backscattering signals of Optical Fiber Tweezers (OFT) has been demonstrated able to discriminate a wide range of microparticles. Barros and Cunha take this a step further by extracting the phase spectral information from OFT backscattering signals. This approach allows for the detection and identification of tumoral cell and extracellular nanovesicle features in complex biological media.

Unprecedented control over the superposition of electronic states of a ‘quantum coral’, by changing the position of a single atom within it, provides a powerful tool for studying the quantum behaviour of matter.

3D higher-order topological insulators (HOTIs) exhibit 1D hinge states depending on extrinsic sample details, while intrinsic features of HOTIs remain unknown. Here, K.S. Lin et al. introduce the framework of spin-resolved topology to show that helical HOTIs can realize a doubled axion insulator phase with nontrivial partial axion angles.

A phenomenon of dynamical Aharonov-Bohm caging arises in a Z2 lattice gauge theory, as a result of vison-like configurations of the gauge-magnetic flux threading elementary plaquettes of the lattice. The authors demonstrate that particles are tightly confined inside the cages, which become mobile in the presence of quantum fluctuations, leading to a Luttinger Liquid or to a Mott insulator of the confined mesons.

A longstanding question in quantum information is the validity of the disputed Peres conjecture stating that bound entangled state can never lead to Bell inequality violation. Here Vértesi and Brunner prove that the Peres conjecture is false by providing an explicit counter example.

In quantum technologies, scalable ways to characterise errors in quantum hardware are highly needed. Here, the authors propose an approximate version of quantum process tomography based on tensor network representations of the processes and data-driven optimisation.

High-dimensional quantum states allow for several advantages in quantum communication, but protocols such as teleportation require additional entangled photons as the dimension increases. Here, the authors show how to transport a high-dimensional quantum state from a bright coherent laser field to a single photon, using two entangled photons as the quantum channel.

Reaching a quantum advantage in metrology usually requires hard-to-prepare two-mode entangled states such as NOON states. Here, instead, the authors demonstrate single-mode phase estimation using Fock states superpositions in a superconducting qubit-oscillator system.

Quantum computing has advantages over conventional computing, but the complexity of quantum algorithms creates technological challenges. Here, an architecture-independent technique, that simplifies adding control qubits to arbitrary quantum operations, is developed and demonstrated.

The authors present an approach to collect and process solution NMR spectra based on steady-state free-precession acquisitions, which can provide higher sensitivity for small organic molecules than currently used Fourier-based counterparts.

Coherent photon sources are essential for quantum technologies like sensing and computing. This work proposes a superconducting circuit design enabling on-chip, tunable photon emission via an external control, offering stable and precise control without disturbing the source dynamics.

Most quantum technologies rely upon quantum wires to ensure the faithful transfer of quantum states between remote locations—a process that is especially vulnerable to decoherence. Yao et al.propose a means to harness topological protection to design a quantum wire that is intrinsically robust against decoherence.

By implementing random circuit sampling, experimental and theoretical results establish the existence of transitions to a stable, computationally complex phase that is reachable with current quantum processors.

Profiling assays measure thousands of features to uncover biological insights but lack reliable methods for quality evaluation. Here, the authors develop a versatile information retrieval framework to robustly quantify sample activity and similarity in large-scale profiling data.