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Helpful disorder in the lungs

Nature Physics - Δευ, 08/06/2020 - 00:00

Nature Physics, Published online: 08 June 2020; doi:10.1038/s41567-020-0896-7

Microscopic motile cilia, beating in synchrony across large scales, move the liquid lining of our lungs, protecting from infection and dirt. Surprisingly, a disordered arrangement of cilia, as observed in nature, is shown to be optimal for airway clearance.

Multi-scale spatial heterogeneity enhances particle clearance in airway ciliary arrays

Nature Physics - Δευ, 08/06/2020 - 00:00

Nature Physics, Published online: 08 June 2020; doi:10.1038/s41567-020-0923-8

Fluid flow through airways—necessary to keep lungs healthy and free from particles—occurs thanks to moving cilia. Here the authors show that defects in the arrangement of these cilia can facilitate particle clearance through the lungs.

Electron acceleration in laboratory-produced turbulent collisionless shocks

Nature Physics - Δευ, 08/06/2020 - 00:00

Nature Physics, Published online: 08 June 2020; doi:10.1038/s41567-020-0919-4

In laser–plasma experiments complemented by simulations, electron acceleration is observed in turbulent collisionless shocks. This work clarifies the pre-acceleration to relativistic energies required for the onset of diffusive shock acceleration.

The katalytic speedometer

Nature Physics - Δευ, 08/06/2020 - 00:00

Nature Physics, Published online: 08 June 2020; doi:10.1038/s41567-020-0938-1

As a unit for enzyme activity, the katal is enigmatic but struggles to find widespread acceptance. Soumitra Athavale tells its story.

Repeated quantum error detection in a surface code

Nature Physics - Δευ, 08/06/2020 - 00:00

Nature Physics, Published online: 08 June 2020; doi:10.1038/s41567-020-0920-y

In a surface code consisting of four data and three ancilla qubits, repeated error detection is demonstrated. The lifetime and coherence time of the logical qubit are enhanced over those of any of the constituent qubits when no errors are detected.

Error-corrected gates on an encoded qubit

Nature Physics - Δευ, 08/06/2020 - 00:00

Nature Physics, Published online: 08 June 2020; doi:10.1038/s41567-020-0931-8

Error-corrected quantum gates that can tolerate dominant errors during the execution of quantum operations have been demonstrated. Substantial improvement of the gate fidelity sheds light on fault-tolerant universal quantum computation.

Evidence for quark-matter cores in massive neutron stars

Nature Physics - Δευ, 01/06/2020 - 00:00

Nature Physics, Published online: 01 June 2020; doi:10.1038/s41567-020-0914-9

The cores of neutron stars could be made of hadronic matter or quark matter. By combining first-principles calculations with observational data, evidence for the presence of quark matter in neutron star cores is found.

Repulsive photons in a quantum nonlinear medium

Nature Physics - Δευ, 01/06/2020 - 00:00

Nature Physics, Published online: 01 June 2020; doi:10.1038/s41567-020-0917-6

Repulsive photons in a quantum nonlinear medium

Generalized bulk–boundary correspondence in non-Hermitian topolectrical circuits

Nature Physics - Δευ, 01/06/2020 - 00:00

Nature Physics, Published online: 01 June 2020; doi:10.1038/s41567-020-0922-9

Boundary-localized bulk eigenstates given by the non-Hermitian skin effect are observed in a non-reciprocal topological circuit. A fundamental revision of the bulk–boundary correspondence in an open system is required to understand the underlying physics.

Atomic superheterodyne receiver based on microwave-dressed Rydberg spectroscopy

Nature Physics - Δευ, 01/06/2020 - 00:00

Nature Physics, Published online: 01 June 2020; doi:10.1038/s41567-020-0918-5

The Rydberg-atom superhet, based on microwave-dressed Rydberg atoms and a tailored electromagnetically induced transparency spectrum, allows SI-traceable measurements of microwave electric fields with unprecedented sensitivity.

Cosmology at the end of the world

Nature Physics - Δευ, 01/06/2020 - 00:00

Nature Physics, Published online: 01 June 2020; doi:10.1038/s41567-020-0909-6

Braneworld cosmologies describe our universe as a four-dimensional membrane embedded in a bulk five-dimensional anti-de Sitter spacetime. In a possible holographic realization, observers on the brane experience cosmology, and gravity is localized.

Independent superconductors and correlated insulators in twisted bilayer graphene

Nature Physics - Δευ, 01/06/2020 - 00:00

Nature Physics, Published online: 01 June 2020; doi:10.1038/s41567-020-0928-3

Here, it is shown that superconductivity can exist without correlated insulating states in twisted bilayer graphene devices a little away from the magic angle. This indicates the two phases compete with each other, in contrast to previous claims.

Growth of concomitant laser-driven collisionless and resistive electron filamentation instabilities over large spatiotemporal scales

Nature Physics - Δευ, 01/06/2020 - 00:00

Nature Physics, Published online: 01 June 2020; doi:10.1038/s41567-020-0913-x

In the interaction of ultraintense, short laser pulses with solid targets, the collisionless Weibel instability is observed. For a sufficiently high resistivity of the target, an additional resistive instability appears.

Emergence of criticality through a cascade of delocalization transitions in quasiperiodic chains

Nature Physics - Δευ, 01/06/2020 - 00:00

Nature Physics, Published online: 01 June 2020; doi:10.1038/s41567-020-0908-7

The localization properties of waves in the quasiperiodic chains described by the Aubry–André model and Fibonacci model are investigated. Passing from one model to the other, the system develops a cascade of delocalization transitions.

Understanding deep learning is also a job for physicists

Nature Physics - Τρί, 26/05/2020 - 00:00

Nature Physics, Published online: 26 May 2020; doi:10.1038/s41567-020-0929-2

Automated learning from data by means of deep neural networks is finding use in an ever-increasing number of applications, yet key theoretical questions about how it works remain unanswered. A physics-based approach may help to bridge this gap.

Tail risk of contagious diseases

Nature Physics - Δευ, 25/05/2020 - 00:00

Nature Physics, Published online: 25 May 2020; doi:10.1038/s41567-020-0921-x

This Perspective argues that an approach called extreme value theory is appropriate for understanding the so-called tail risk of epidemic outbreaks, in particular by demonstrating that the distribution of fatalities due to epidemic outbreaks over the past 2500 years is fat-tailed and dominated by extreme events.

Tunable bandgap renormalization by nonlocal ultra-strong coupling in nanophotonics

Nature Physics - Δευ, 25/05/2020 - 00:00

Nature Physics, Published online: 25 May 2020; doi:10.1038/s41567-020-0890-0

When interfacing a graphene layer with a thin solid emitter, the quantum plasmonic vacuum allows each solid electron to access all unoccupied valence states through the nonlocality of their light-matter interaction, creating ultra-strong coupling alongside mass and bandgap renormalization.

Hard antinodal gap revealed by quantum oscillations in the pseudogap regime of underdoped high-<i>T</i><sub>c</sub> superconductors

Nature Physics - Δευ, 25/05/2020 - 00:00

Nature Physics, Published online: 25 May 2020; doi:10.1038/s41567-020-0910-0

A careful study of quantum oscillations of single crystals of the cuprate superconductor YBCO placed under a magnetic field reveals a sawtooth behaviour that is reminiscent of two-dimensional electronic systems—in turn suggesting the existence of a so-called ‘hard antinodal gap’ in this system.

High-fidelity entanglement and detection of alkaline-earth Rydberg atoms

Nature Physics - Δευ, 25/05/2020 - 00:00

Nature Physics, Published online: 25 May 2020; doi:10.1038/s41567-020-0903-z

High entanglement fidelity between neutral atoms is achieved using highly excited Rydberg states. The unique electron structure provided by alkaline-earth atoms makes it a promising platform for various quantum-technology-based applications.

A boost to Rydberg quantum computing

Nature Physics - Δευ, 25/05/2020 - 00:00

Nature Physics, Published online: 25 May 2020; doi:10.1038/s41567-020-0907-8

Systems of neutral atoms are gradually gaining currency as a promising candidate for realizing large-scale quantum computing. The achievement of a record-high fidelity in quantum operation with alkaline-earth Rydberg atoms is a case in point.

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