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Systemic resilience in economics

Nature Physics - Tue, 12/04/2022 - 00:00

Nature Physics, Published online: 12 April 2022; doi:10.1038/s41567-022-01581-4

Drawing on notions from non-equilibrium physics, an interdisciplinary team of economists and scientists describe a framework for understanding the factors that underpin economic resilience, and identify the basic tools for implementing it.

Encounter with a stranger metal

Nature Physics - Mon, 11/04/2022 - 00:00

Nature Physics, Published online: 11 April 2022; doi:10.1038/s41567-022-01573-4

Low-temperature measurements on twisted bilayer graphene show that the exotic ‘strange metal’ state is almost certainly caused by interactions between electrons.

Quantum critical behaviour in magic-angle twisted bilayer graphene

Nature Physics - Mon, 11/04/2022 - 00:00

Nature Physics, Published online: 11 April 2022; doi:10.1038/s41567-022-01556-5

The presence or absence of a strange metal phase in twisted bilayer graphene has been controversial. Now, measurements over a wide range of temperature and doping give much stronger evidence for its existence.

Entropy-driven order in an array of nanomagnets

Nature Physics - Thu, 07/04/2022 - 00:00

Nature Physics, Published online: 07 April 2022; doi:10.1038/s41567-022-01555-6

Long-range order is normally related to an entropy decrease. Yet, an increase in entropy in one part of a system can induce long-range order in another. A new form of such entropy-driven order is now demonstrated in an artificial spin-ice system.

Double trouble

Nature Physics - Mon, 04/04/2022 - 00:00

Nature Physics, Published online: 04 April 2022; doi:10.1038/s41567-022-01584-1

Experiments show that interactions between electrons in twisted bilayer graphene can create a spatial order that doubles the size of the twisted unit cell.

Noble-gas and alkali spins exchange excitations

Nature Physics - Mon, 04/04/2022 - 00:00

Nature Physics, Published online: 04 April 2022; doi:10.1038/s41567-022-01568-1

Noble gas nuclear spins can store quantum information for hours but are hard to control. Creating a large coherent coupling to an alkali vapour gives a route to manipulating the collective nuclear spin of a helium-3 gas.

Broken-symmetry states at half-integer band fillings in twisted bilayer graphene

Nature Physics - Mon, 04/04/2022 - 00:00

Nature Physics, Published online: 04 April 2022; doi:10.1038/s41567-022-01557-4

Correlated insulating states are common in twisted bilayer graphene when the density of carriers is close to an integer per moiré unit cell. Now, such states emerge at half-integer fillings and show signs of being spin or charge density waves.

Real-space imaging of phase transitions in bridged artificial kagome spin ice

Nature Physics - Mon, 04/04/2022 - 00:00

Nature Physics, Published online: 04 April 2022; doi:10.1038/s41567-022-01564-5

Artificial spin ice formed of nanomagnets arranged on a lattice mimics frustrated magnetism seen in condensed matter. By controlling magnetic interactions, theoretically predicted phase transitions are now observed in artificial kagome-lattice spin ice.

Strong coupling of alkali-metal spins to noble-gas spins with an hour-long coherence time

Nature Physics - Mon, 04/04/2022 - 00:00

Nature Physics, Published online: 04 April 2022; doi:10.1038/s41567-022-01535-w

The nuclear spins of noble gases are isolated from sources of decoherence but also from external control fields. Optically addressable alkali-metal atoms can couple strongly to noble-gas spins, potentially providing a mechanism for coherent control.

Publisher Correction: Non-specific adhesive forces between filaments and membraneless organelles

Nature Physics - Fri, 01/04/2022 - 00:00

Nature Physics, Published online: 01 April 2022; doi:10.1038/s41567-022-01600-4

Publisher Correction: Non-specific adhesive forces between filaments and membraneless organelles

A controlled cascade interference

Nature Physics - Thu, 31/03/2022 - 00:00

Nature Physics, Published online: 31 March 2022; doi:10.1038/s41567-022-01587-y

Nonlinear optical effects enable sophisticated functionalities to generate and manipulate light. The precise control of two distinct nonlinear phenomena in a photonic chip can enhance a key optical nonlinearity that makes single-photon sources more efficient.

In situ control of effective Kerr nonlinearity with Pockels integrated photonics

Nature Physics - Thu, 31/03/2022 - 00:00

Nature Physics, Published online: 31 March 2022; doi:10.1038/s41567-022-01542-x

Many nanophotonic devices rely on optical nonlinearities, which can be indirectly engineered. The quantum interference of different nonlinear pathways directly controls the Kerr nonlinearity without changing the device design.

Formation of matter-wave polaritons in an optical lattice

Nature Physics - Thu, 31/03/2022 - 00:00

Nature Physics, Published online: 31 March 2022; doi:10.1038/s41567-022-01565-4

Polaritons are quasiparticles created through the coupling of matter excitations and light. A cold-atom experiment using matter waves instead of photons reports the observation of analogues of polaritons with tunable properties and no dissipation.

Random circuits have no shortcuts

Nature Physics - Mon, 28/03/2022 - 00:00

Nature Physics, Published online: 28 March 2022; doi:10.1038/s41567-022-01559-2

Theoretical physicists studying black holes have produced a conjecture that random quantum circuits cannot be simplified. Now, a minimal version of this conjecture has been proven, reaching a milestone in quantum-circuit complexity theory.

Linear growth of quantum circuit complexity

Nature Physics - Mon, 28/03/2022 - 00:00

Nature Physics, Published online: 28 March 2022; doi:10.1038/s41567-022-01539-6

The dynamics of quantum states underlies the emergence of thermodynamics and even recent theories of quantum gravity. Now it has been proven that the quantum complexity of states evolving under random operations grows linearly in time.

Manipulation of Dirac band curvature and momentum-dependent <i>g</i> factor in a kagome magnet

Nature Physics - Mon, 28/03/2022 - 00:00

Nature Physics, Published online: 28 March 2022; doi:10.1038/s41567-022-01558-3

The change in a band structure when a magnetic field is applied should depend on the momentum of the electronic state, but this is hard to measure. Now, this effect is demonstrated in a topological magnet.

Inverse Occam’s razor

Nature Physics - Mon, 28/03/2022 - 00:00

Nature Physics, Published online: 28 March 2022; doi:10.1038/s41567-022-01575-2

Scientists have long preferred the simplest possible explanation of their data. More recently, a worrying trend to favour unnecessarily complex interpretations has taken hold.

A spotlight on circular states

Nature Physics - Thu, 24/03/2022 - 00:00

Nature Physics, Published online: 24 March 2022; doi:10.1038/s41567-022-01572-5

Circular Rydberg states provide an ideal resource for large-scale quantum computing and simulation. These circular states can be controlled using coherent optical pulses, providing a route to programmable quantum hardware.

Non-specific adhesive forces between filaments and membraneless organelles

Nature Physics - Thu, 24/03/2022 - 00:00

Nature Physics, Published online: 24 March 2022; doi:10.1038/s41567-022-01537-8

Many organelles in the cell are not encapsulated in a membrane—they are liquid-like domains formed through phase separation. The liquid-like nature of such domains leads to adhesive interactions between the cytoskeleton filaments and organelles.

Simulation of open quantum systems by automated compression of arbitrary environments

Nature Physics - Thu, 24/03/2022 - 00:00

Nature Physics, Published online: 24 March 2022; doi:10.1038/s41567-022-01544-9

It is difficult to analyse open quantum systems because an accurate description of their environments becomes intractably large. A method that automatically identifies an efficient representation provides a flexible approach to numerical simulations.

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University of Crete - Department of Physics  - Voutes University Campus - GR-70013 Heraklion, Greece
phone: +30 2810 394300 - email: chair@physics.uoc.gr