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A coherent nanomechanical oscillator driven by single-electron tunnelling

Nature Physics - Δευ, 14/10/2019 - 00:00

Nature Physics, Published online: 14 October 2019; doi:10.1038/s41567-019-0683-5

In a nanobeam that is strongly coupled to a single-electron transistor, electron tunnelling back-action induces self-sustaining mechanical oscillations. This oscillator can be compared to a phonon laser and can be stabilized.

Jigsaw puzzle design of pluripotent origami

Nature Physics - Δευ, 14/10/2019 - 00:00

Nature Physics, Published online: 14 October 2019; doi:10.1038/s41567-019-0677-3

The crease patterns for origami-based mechanical metamaterials can fold into myriad 3D shapes, but predicting foldability is no simple task. A framework for designing foldable patterns offers a neat alternative to extensive computer optimization.

A fold strategy

Nature Physics - Δευ, 14/10/2019 - 00:00

Nature Physics, Published online: 14 October 2019; doi:10.1038/s41567-019-0684-4

It is generally difficult to know in advance if a sheet of paper can be folded into an origami shape, but for quadrilateral crease patterns a tiling approach can identify all possible ways of folding them.

Light emission based on nanophotonic vacuum forces

Nature Physics - Δευ, 14/10/2019 - 00:00

Nature Physics, Published online: 14 October 2019; doi:10.1038/s41567-019-0672-8

Vacuum fluctuations in the vicinity of nanophotonic structures can lead to the conversion of a free electron into a polariton and a high-energy photon, whose frequency can be controlled by the electromagnetic properties of the nanostructure.

Author Correction: Femtosecond-resolved observation of the fragmentation of buckminsterfullerene following X-ray multiphoton ionization

Nature Physics - Πέμ, 10/10/2019 - 00:00

Nature Physics, Published online: 10 October 2019; doi:10.1038/s41567-019-0706-2

Author Correction: Femtosecond-resolved observation of the fragmentation of buckminsterfullerene following X-ray multiphoton ionization

Vibrational spectroscopy at atomic resolution with electron impact scattering

Nature Physics - Δευ, 07/10/2019 - 00:00

Nature Physics, Published online: 07 October 2019; doi:10.1038/s41567-019-0675-5

Conventional on-axis electron energy-loss spectroscopy can detect vibrational modes in crystals and amorphous solids at atomic resolution by isolating the specific signal from the background signal and the dipole contributions.

Cooling and self-oscillation in a nanotube electromechanical resonator

Nature Physics - Δευ, 07/10/2019 - 00:00

Nature Physics, Published online: 07 October 2019; doi:10.1038/s41567-019-0682-6

The back-action of electrons can cool a nanomechanical oscillator to a few-quantum state when a current flows through a suspended nanotube. The electron back-action, which is attributed to an electrothermal effect, also induces self-oscillations.

Microwave-to-optics conversion using a mechanical oscillator in its quantum ground state

Nature Physics - Δευ, 07/10/2019 - 00:00

Nature Physics, Published online: 07 October 2019; doi:10.1038/s41567-019-0673-7

Electro-optomechanical conversion between optical and microwave photons is achieved with minimal added noise by cooling the mechanical oscillator to its quantum ground state. This has potential for future coherence-preserving transduction.

Enhanced thermal Hall effect in the square-lattice Néel state

Nature Physics - Δευ, 07/10/2019 - 00:00

Nature Physics, Published online: 07 October 2019; doi:10.1038/s41567-019-0669-3

The remarkably large thermal Hall response recently observed in the copper oxides challenges our understanding of the excitations in an insulating antiferromagnet. Here, a possible explanation of the underlying physics is provided.

Exceptional quantum behaviour

Nature Physics - Δευ, 07/10/2019 - 00:00

Nature Physics, Published online: 07 October 2019; doi:10.1038/s41567-019-0657-7

Non-Hermitian systems with gain and loss give rise to exceptional points with exceptional properties. An experiment with superconducting qubits now offers a first step towards studying these singularities in the quantum domain.

Atomic-scale fragmentation and collapse of antiferromagnetic order in a doped Mott insulator

Nature Physics - Δευ, 07/10/2019 - 00:00

Nature Physics, Published online: 07 October 2019; doi:10.1038/s41567-019-0671-9

Spin-polarized tunnelling data show that the breakdown of antiferromagnetic order and the collapse of the spectral gap are not correlated in Sr2IrO4. This indicates that short-range magnetic correlations are not behind the emergence of the pseudogap.

Extreme magnetic field-boosted superconductivity

Nature Physics - Δευ, 07/10/2019 - 00:00

Nature Physics, Published online: 07 October 2019; doi:10.1038/s41567-019-0670-x

The recently discovered spin-triplet superconductor UTe2 is found to display a number of other ‘re-entrant’ superconducting phases under ultrahigh magnetic fields.

Quantum state tomography across the exceptional point in a single dissipative qubit

Nature Physics - Δευ, 07/10/2019 - 00:00

Nature Physics, Published online: 07 October 2019; doi:10.1038/s41567-019-0652-z

The dynamics of a single dissipative qubit undergoing non-Hermitian quantum dynamics in the vicinity of an exceptional point is experimentally studied in a superconducting transmon circuit.

Wind analysis links West Antarctic ice loss to humans

Physics Today - Τρί, 01/10/2019 - 10:01
Physics Today, Volume 72, Issue 10, Page 14-15, October 2019.
Anthropogenic warming is reversing the predominant winds over the region and could explain the ice sheet’s destabilization.

Wind analysis links West Antarctic ice loss to humans

Physics Today - Τρί, 01/10/2019 - 10:01
Physics Today, Volume 72, Issue 10, Page 14-15, October 2019.
Anthropogenic warming is reversing the predominant winds over the region and could explain the ice sheet’s destabilization.

Massive galaxies from the early universe found hiding in plain sight

Physics Today - Τρί, 01/10/2019 - 10:01
Physics Today, Volume 72, Issue 10, Page 16-18, October 2019.
Detection at a new wavelength reveals ancient galaxies in higher numbers than observed previously or predicted.

Massive galaxies from the early universe found hiding in plain sight

Physics Today - Τρί, 01/10/2019 - 10:01
Physics Today, Volume 72, Issue 10, Page 16-18, October 2019.
Detection at a new wavelength reveals ancient galaxies in higher numbers than observed previously or predicted.

A molecular clock for testing fundamental forces

Physics Today - Τρί, 01/10/2019 - 10:01
Physics Today, Volume 72, Issue 10, Page 18-21, October 2019.
The vibrational frequencies of trapped ultracold molecules can serve as a check on what we think we know about the universe.

A molecular clock for testing fundamental forces

Physics Today - Τρί, 01/10/2019 - 10:01
Physics Today, Volume 72, Issue 10, Page 18-21, October 2019.
The vibrational frequencies of trapped ultracold molecules can serve as a check on what we think we know about the universe.

A folding protein gets caught in the act

Physics Today - Τρί, 01/10/2019 - 10:01
Physics Today, Volume 72, Issue 10, Page 21-23, October 2019.
Time-resolved NMR spectra paint a picture of structural transformation with millisecond resolution.

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