Research Briefing

Bacteria can sustain spatial protein oscillations for a remarkably wide range of protein concentrations. The robustness arises from a conformational switch of a key protein between latent versus active states.

Symmetry breaking is routinely observed in isolated systems, where perturbations propagate through the system. For out-of-equilibrium systems, however, perturbations are predicted to diffuse; and this key signature of spontaneous symmetry breaking has now been observed in a polariton quantum fluid.

Photon interactions in materials typically create a gaseous bosonic state, which is prone to turbulent behaviour that disrupts coherence. But it is now shown that, using fast-gain processes in a modulated semiconductor laser, light can be stabilized in a liquid-like state, enhancing the coherence of its flow.

A two-dimensional spectroscopic technique to probe the strength of electron–phonon coupling has the capability to simultaneously resolve the phonon mode and the electron transition energy — and is bringing fresh insight into the complex interactions of phonons and electrons in a range of materials.

Second messengers are intracellular signalling molecules that relay environmental changes and prompt cellular responses. Through an information-theory framework coupled with quantitative experiments, the second-messenger molecule cAMP, in the bacterium Pseudomonas aeruginosa, is shown to achieve information transmission rates of up to 40 bits per hour.

Light-switchable enzymes hold great promise for mediating molecular activations in living cells, yet their full potential in realizing versatile controls in nonlinear networks remains unexplored. Now, optical control is demonstrated over a key enzyme involved in animal cell division, and a diverse array of dynamic cell shapes is achieved by biochemically hacking an endogenous signalling circuit.

Quantum electrodynamics (QED) is a cornerstone of the standard model of particle physics. A decade-long effort to simulate QED on a two-dimensional lattice has now succeeded — through the use of a trapped-ion quantum computer based on multidimensional ‘qudits’, which are uniquely suited to the challenge.

Ultra-low-temperature scanning tunnelling spectroscopy measurements indicate that twisting the layers in heterostructures making up a single layer of superconducting NbSe₂ on graphene leads to momentum-dependent changes in the superconducting gap. This ability could enable the development of artificial superconductors with nontrivial magnetic and topological properties.

We have tested key modelling assumptions of intestinal organoid morphogenesis via biophysical and pharmacological experiments. We have found that mechano-sensitive feedback on cytoskeletal tension gives rise to morphological bistability, and that the same mechanical perturbation can have drastically different effects on morphogenesis depending on the timing of application. This multicellular bistability can provide robustness to developmental systems.

False vacuum decay is a process of fundamental importance in quantum field theory. Here, a 5,564-qubit quantum annealer is used to simulate the dynamics of false vacuum decay and observe the formation of bubbles of true vacuum. This approach could provide insight into the role of phase transitions in the early Universe.

Among weakly interacting bosons, quantum fluctuations are akin to those of harmonic oscillators, and they manifest themselves through positive correlations between particles of opposite momenta. A quantum-gas experiment reveals that, by cranking up the interactions, these correlations are suppressed, and hence that quantum fluctuations become strong and anharmonic.

In a device comprising two double quantum dots separated by a 250-μm-long superconducting resonator, virtual photons in the resonator are shown to mediate the coupling of electron spins between the quantum dots. When the spin–spin coupling is activated for a controlled duration, oscillations between the spins are observed.

Quantum geometry gives rise to many fascinating phenomena in solids that go beyond Landau theory. A general framework is now introduced to measure the quantum geometric tensor in solids — a fundamental physical quantity that encodes the complete geometric information of the Bloch state.

A tunable SU(2) gauge field has been realized experimentally in a Raman momentum lattice using ultracold atoms. The chiral dynamics of the system have been investigated under different gauge potentials, whose non-Abelian nature was confirmed through observation of the non-Abelian Aharonov–Bohm effect.

Approximate notions of quantum error-correcting codes hold wide importance across quantum information and physics, but are not cohesively understood. Now, general rigorous connections established between approximate quantum error correction and quantum circuit complexity reveal a ‘complexity phase diagram’ for generalized quantum codes — and create a new unifying lens on complex quantum systems.

A bright, ultrashort X-ray pulse is used to transiently create and characterize warm dense copper. As the pulse intensity is increased, the opacity of copper is strongly altered. The recorded X-ray absorption spectra, substantiated by a theoretical electronic structure model, provide insight into the non-equilibrium electron dynamics during the formation of warm dense matter.

Angle-resolved photoemission spectroscopy measurements identify dark electron states in palladium diselenide, cuprate superconductors, and lead halide perovskites. These dark states are attributed to the two pairs of sublattices in each of the solids, which leads to a double two-level quantum system in which double destructive interference can occur.

Spin-squeezed states are a resource for quantum-enhanced precision measurement. However, the theoretical foundations for scalable spin squeezing — where quantum enhancement grows with system size — have only been established for systems exhibiting all-to-all interactions. Now, by unveiling a connection to finite-temperature magnetism, scalable squeezing is extended to locally interacting systems.

A quantum control technique is used to directly couple trapped-ion motional modes with high fidelity, enabling non-destructive measurements of the quantum harmonic oscillator states of atomic motion. The strong coupling rate and precise manipulation of the quantum states achieved with this technique could lead to advances in quantum information processing.

Many 2D or 1D materials feature fascinating collective behaviour of electrons that competes with highly localized interactions at atomic defects. By combining terahertz spectroscopy with scanning tunnelling microscopy, the ultrafast motion of these collective states can be captured with atomic spatial resolution, enabling the observation of electron dynamics at their intrinsic length and time scale.