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Qudits, higher-dimensional analogues of qubits, expand quantum state space for information processing using fewer physical units. Here the authors demonstrate control over a 16-dimensional Hilbert space, equivalent to four qubits, using combined electron-nuclear states of a single Sb donor atom in Si.

Using quantum gas microscopy, Hilbert space fragmentation and fractonic excitations are observed in a two-dimensional tilted Bose–Hubbard model.

For some states in quantum gravity, notions of locality can deviate from effective field theory predictions. Here, the authors show that such deviations can be recast in the quantum information framework of “overlapping qubits”.

Differential isoform usage is identified with high statistical power from spatial transcriptomics data.

Qutrits, or quantum three-level systems, can provide advantages over qubits in certain quantum information applications, and high-fidelity single-qutrit gates have been demonstrated. Goss et al. realize high-fidelity entangling gates between two superconducting qutrits that are universal for ternary computation.

Standard ways of characterising quantum states incur exponential overhead. Here, the authors consider the task of reconstructing density matrices of multimode continuous variable systems, and demonstrate a method which scales polynomially with the system size, provided the state lies in a polynomial dimensional subspace.

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.

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

Development of the Late Cenozoic Ice Age and Late Paleozoic Ice Age follows a comparable climate trajectory, involving secular trends superimposed with multiple astronomically forced climate-carbon cycles and transient climatic events.

The spectral gap problem—whether the Hamiltonian of a quantum many-body problem is gapped or gapless—is rigorously proved to be undecidable; there exists no algorithm to determine whether an arbitrary quantum many-body model is gapped or gapless, and there exist models for which the presence or absence of a spectral gap is independent of the axioms of mathematics.

A large nuclear spin has been successfully placed in a Schrödinger cat state, a superposition of its two most widely separated spin coherent states. This can be used as an error-correctable qubit.

This study provides direct neurophysiological evidence from over 30 human subjects showing that the anterior and posterior hippocampus are functionally distinct, with differences in theta activity linked to recollection and novelty processing.

The hippocampus can replay long spatial sequences without ripples. When present, ripples cluster in spatially restricted zones as a function of replayed location that remap with barrier changes, implying a tagging role in consolidation.

Complex-valued neural networks can recognize phase-sensitive data in wave-related phenomena. Here, authors report a complex-valued optical convolution accelerator operating at over 2 TOPS for recognition of radar images, represents advances towards real-time analysis of complex satellite data.

Experimental measurements of high-order out-of-time-order correlators on a superconducting quantum processor show that these correlators remain highly sensitive to the quantum many-body dynamics in quantum computers at long timescales.

The single-cell gene expression changes during spinal cord formation and neurogenesis in mice are unclear. Here, the authors use a HES5 reporter to live image, then mathematically model, oscillations in single cells in presumed progenitors and neurons of the developing spinal cord.

Xenotransplantation of a genetically edited pig kidney with a thymic autograft into a brain-dead human for 61 days with immunosuppression resulted in stable kidney function without proteinuria, and xenograft rejection was treated and reversed by the end of the study.

Integral equations are used in science and engineering to model complex systems with non-local dependencies; however, existing traditional and machine-learning-based methods cannot yield accurate or efficient solutions in several complex cases. Zappala and colleagues introduce a neural-network-based method that can learn an integral operator and its dynamics from data, demonstrating higher accuracy or scalability compared with several state-of-the-art methods.

Quantum state tomography is the process of retrieving the values that define a quantum system, but realizing it experimentally can be burdensome. Here, the authors provide an alternative approach via the expectation values of a set of non-Hermitian matrices, and characterize a 100,000-dimensional state.

Quantum supremacy is demonstrated using a programmable superconducting processor known as Sycamore, taking approximately 200 seconds to sample one instance of a quantum circuit a million times, which would take a state-of-the-art supercomputer around ten thousand years to compute.

Bosonic qubits can be engineered to feature intrinsic protection against certain kinds of errors, which makes quantum error correction across many bosonic qubits possible with less overhead.

Gaggioli, Lo et al. show that the histone methyltransferase EHMT2/G9a catalyses heterochromatin assembly at stressed replication forks. Untimely heterochromatin disassembly by demethylase KDM3A exposes forks to PRIMPOL-mediated genome instability.

The enteric nervous system regulates gut function but is difficult to study due to sparse neuron distribution and gut motion. Here, the authors showcase a bioelectronic implant for electrophysiological monitoring of the enteric neural activity in freely-behaving animals.

Using voltage imaging, the authors show that interneurons in the hippocampus sharpen memory-encoding-activity by increasing the signal-to-noise ratio of pyramidal neuron sensory representations during working memory in mice.

Coherent noise affecting a random error correcting code is now shown to produce a transition between phases that accumulate and destroy magic.

The use of time-bin entangled qudits is hindered by the phase instability, timing inaccuracy and low scalability of current interferometric schemes. Here, the authors show a fiber-pigtailed photonic chip for generating and processing picosecond-spaced time-bin entangled qudits and utilize the system to implement a quantum key distribution protocol.

A violation of Bell's inequality, which is a direct proof of entanglement, can be observed in the solid state using the electron and nuclear spins of a single phosphorus atom in silicon.

Timing is key for efficient coding and communication across brain areas. Here, the authors found that the medial septum orchestrates hippocampal network activity at multiple temporal scales likely mediating memory encoding and retrieval.

Understanding surface carrier dynamics enables the design of optimal optoelectronic devices. Yang et al. find that surface recombination limits the total carrier lifetime in polycrystalline lead iodide perovskite films, meaning recombination at surfaces is more important than within and between grains.

Critical slowing (associated with increased variance and autocorrelation) can precede critical state transitions. Here, the authors show critical slowing can be used as a marker in seizure forecasting algorithms.

Superconducting quantum processors need to balance intentional disorder (to protect qubits) and nonlinear resonator coupling (to manipulate qubits), while avoiding chaotic instabilities. Berke et al. use the techniques of many-body localization theory to study the stability of current platforms against quantum chaos.

Superconductivity reported in metals driven away from equilibrium via optical pumping has been proposed to arise from nonlinear coupling between electrons and optically excited phonons. The authors use an exact approach to show that here, disorder, which disfavors superconductivity, emerges even though the system is translationally invariant.

A method to engineer higher-order interactions between photons provides a route to create non-classical and entangled states across multiple modes.

The magnetocaloric effect is well understood in spin-frustrated low-dimensional systems, and should be observable in certain high-symmetry molecular structures. Here, the authors report the experimental observation of sub-Kelvin cooling with a molecular magnet, and probe the low-temperature spin behaviour.

The segmentation motor activity of the small intestine is believed to be a result of alternating inhibitory and excitatory neural activity. Huizinga et al.show that the segmentation motor pattern is in fact a result of phase–amplitude interactions of slow-wave activities generated by two networks of interstitial cells of Cajal.

It is generally believed that most eigenstates of quantum chaotic models are ergodic. In this work, the authors disprove this by showing that all eigenstates of the Dicke model in the chaotic regime are scarred, and that ergodicity is an ensemble property, achievable only in the temporal average.

The whisking oscillator—consisting of parvalbumin-expressing inhibitory neurons located in the vibrissa intermediate reticular nucleus—in mice is an all-inhibitory network and recurrent synaptic inhibition has a key role in its rhythmogenesis.

Humans have a capacity for hierarchical cognitive control—the ability to simultaneously control immediate actions while holding more abstract goals in mind. The authors show that neural oscillations establish dynamic communication networks within the frontal cortex and that these oscillations coordinate local neural activity with increasing cognitive control.

Superconducting giant atoms are realized in a waveguide by coupling small atoms to the waveguide at multiple discrete locations, producing tunable atom–waveguide coupling and enabling decoherence-free interactions.

Multimodal results (iEEG, fMRI and MEG) of predictions from integrated information theory and global neuronal workspace theory align with some predictions of both theories on visual consciousness, but also critically challenge key tenets of both theories.

In addition to light intensity, changes in pupil diameter are correlated with mental effort, attention and levels of arousal. Reimer et al. report that across behavioural states, fluctuations in pupil diameter are highly correlated with activity of noradrenergic and cholinergic projection neurons.

Quantum spin-ice phases are predicted to have emergent gauge fields and fractionalization. Neutron scattering and thermodynamic measurements of the quantum spin-ice candidate Ce₂Zr₂O₇ show features consistent with these predictions.

Signal processing is key to communications and video image processing for astronomy, medical diagnosis, autonomous driving, big data and AI. Menxi Tan and colleagues report a photonic processor operating at 17Tb/s for ultrafast robotic vision and machine learning.

Motor patterns underlying the rodent exploratory behaviours whisking and sniffing are coordinated by respiratory centres in the ventral medulla; a distinct region in the ventral medulla provides rhythmic input to the facial motor neurons that drive scanning by the vibrissae, and input from the pre-Bötzinger complex coordinates whisking with sniffing and basal breathing.

Flinker and colleagues describe a framework for auditory cortical asymmetries that capitalizes on spectrotemporal modulation space. Data from psychophysics, magnetoencephalography (MEG) and electrocorticography (ECoG) inform a signal processing-based view on lateralization.