Nature Physics

This month we celebrate Nature Physics' twentieth birthday, consider the flexoelectricity of water ice, and feature a Perspective on chiral phonons. Have a look at go.nature.com/NPoct25

Directly observing how a coherent global phase forms has long been challenging. Now an incoherent magnon gas is observed to transform into a state with a macroscopic global phase, confirming a key prediction of Bose–Einstein condensation theory. nature.com/articles/s4156…

Quantum error correction typically encodes one logical qubit across many physical qubits. An experiment now encodes and corrects a qubit within the multiple internal states of a single trapped ion, reducing errors and extending the coherence time. nature.com/articles/s4156…

A factor that limits the energy gain in laser–plasma accelerators is dephasing between the accelerated electrons and the laser pulse. Now a proof-of-concept experiment shows that the dephasing limit can be overcome with a flying focus. nature.com/articles/s4156…

Spectroscopy of quantum many-body systems often relies on Fermi’s golden rule, but its regime of validity is unclear. Now measurements in a strongly interacting Fermi gas map the probe dynamics and identify where the rule holds and breaks down. nature.com/articles/s4156…

Bosonic quantum states can be understood as superpositions of eigenstates with fixed numbers of bosons. Now experiments show that mapping this representation to classical wave propagation offers an intuitive way to manipulate large quantum states. nature.com/articles/s4156…

Phonon decoherence in quantum high-overtone bulk acoustic-wave resonators is dominated by imperfections under the material surface. Removing the damaged subsurface layer substantially increases the performance of these devices. nature.com/articles/s4156…

Condensing ultracold polar molecules requires efficient cooling despite collisional losses. Now sodium–rubidium molecules have been brought to condensation and tuned into a self-bound droplet through control of their dipolar interactions. nature.com/articles/s4156…

Understanding loss mechanisms in nanomechanical resonators has enabled ultracoherent devices with improved sensitivity. Now these resonators are found to be sensitive to non-contact friction from nearby materials, thus limiting mechanical coherence. nature.com/articles/s4156…

How individual doped holes turn into superconducting Cooper pairs as doping increases in unconventional superconductors is still not well understood. Now, this process is observed in a paradigmatic cuprate compound. nature.com/articles/s4156…

Localized core vacancies in molecules decay via an Auger–Meitner cascade to form diffuse valence holes. X-ray scattering is now used to measure the change in the electron-pair density, resolving the spatial redistribution of electrons. nature.com/articles/s4156…

Whether orbital order can exist with a clear band-structure fingerprint in correlated materials has remained unresolved. Now an orbital order from rare earth 5d electrons without structural or magnetic order is seen in an intermetallic compound. nature.com/articles/s4156…

Single molecules that host isolated spins are promising candidates for applications in quantum technologies. Now it is shown that exchange interactions enable electric control of spins in two different molecular species. nature.com/articles/s4156…

Cell intercalation is an exchange of cell neighbours. Now it is shown in a minimal system of four cells that intercalation is driven by junction tension and migratory forces. nature.com/articles/s4156…

Interacting electron spins in solid-state devices could be used for quantum networks, but such spins are often too closely spaced to be individually addressed. Single-spin control has now been demonstrated for interacting rare-earth dopants. nature.com/articles/s4156…

Direct measurements linking fermionic pairing to macroscopic superflow have now been achieved across the BEC–BCS crossover using a Sagnac-like phonon interferometer to measure the quantum of angular momentum per particle. nature.com/articles/s4156…

Long-range magnetic order in low-dimensional systems depends on dimensionality and magnetic anisotropy. Now self-intercalation has been shown to tune a crossover from 3D Heisenberg to 2D Ising ferromagnetism in Fe₃GeTe₂. nature.com/articles/s4156…

Floquet engineering could, in principle, induce a topological phase in semiconductors, but clear evidence has been lacking. Now it is shown in SnTe that femtosecond light pulses briefly create a topological state that is absent at equilibrium. nature.com/articles/s4156…

Shared quantum entanglement can be used to transfer quantum states from one location to another. An experiment has now demonstrated this transfer with higher efficiency than directly sending single photons through a lossy channel. nature.com/articles/s4156…

In a geometrical theory for the fractional quantum Hall effect, chiral spin-2 neutral excitations arise. Now, multiple such excitations are observed and provide evidence for the parton description of the quantum Hall effect. nature.com/articles/s4156…

Fruit fly sperm is substantially longer than the sac in which it is stored. It is now shown that reciprocal pushing between thousands of sperm maintains them in a motile and unentangled state in the sac. nature.com/articles/s4156…