Research articles

The ability to orient atomic spins via optical pumping has important implications for the fields of quantum information and metrology, and while polarization typically occurs parallel to the optical axis, it is often desirable to orient spins along a transverse magnetic field. This work demonstrates an optical pumping scheme for transverse orientation of the spin of cesium vapor, allowing control of spin trajectories.

Much of science revolves around predicting the future and retrodicting the past. In this study, the authors develop a theoretical framework that prescribes how the transition rates of a generic stochastic system should be perturbed so that the system becomes more susceptible to prediction or retrodiction, and demonstrate their method on two concrete systems: diffusion on a random network, and a thermalizing quantum harmonic oscillator.

Excitons are neutral quasiparticles, which are investigated as a potential component to improve the performance of photovoltaic cells however it is first necessary to develop methods to achieve multiexciton generation such as singlet fission. To this end the authors theoretically and experimentally demonstrate long-lived triplet exciton states via singlet fission enabled by the intermolecular coupling geometries in pentacene films.

Hofstadter’s butterfly is a fractal pattern which pictorially represents the behavior of electrons under an applied magnetic field in a 2D lattice as a pair of butterfly wings. Here, the authors recreate this pattern by measuring the acoustic density of states in a fine-tuned one-dimensional acoustic array.

Electrons have been used to map the structural properties of materials since the discovery of the particle-wave duality, while recent advances in ultrafast electron sources enabled time-resolved electron scattering techniques to probe atomic-scale structural dynamics with femtosecond temporal accuracy. The authors demonstrate ultrafast nano-diffraction with relativistic beams as well as scanning transmission electron microscopy enabling them to probe the micro-texture in complex heterogeneous materials.

Nanoparticle carriers are increasingly used for targeted drug delivery and other medical applications and ideally one would want several functionalities associated with one single nanocarrier. The authors report a method to improve collection and minimize aggregation of plasma polymerized nanoparticles by modifying the substrate design on which they are collected from a typical 2D geometry into a series of well-like structures which increase sample yield as well as inhibiting their fusion with the substrate itself.

The aim of quantum communications is to transmit quantum information at high rate over long distances, something that can only be achieved by quantum repeaters and quantum networks. Here the author presents the ultimate end-to-end capacities of a quantum network, also showing the advantages of multipath network routing versus single repeater chains.

Antiferromagnets are expected to be a key part of next generation electronic devices however their magnetic interactions prove difficult to access. Here, the authors demonstrate that the surface sensitive spin-Hall magnetoresistance, along with a simple analytical model, can successfully probe the internal anisotropies of the model antiferromagnet hematite (α-Fe₂O₃).

The experimental realisation of a Kondo lattice and the interplay with Mott–Hubbard charge localisation is one of the many challenges in condensed matter physics. The authors deposit f-elements onto a metallic substrate to elucidate the conditions required to obtain a Kondo lattice on a superlattice and investigate the interplay with the Mott physics.

Systems composed of neutral atoms and photons provide an ideal platform for the emerging field of quantum non-linear optics, which in turn is of interest for quantum technologies and the study of many-body physics. The authors theoretically propose a hybrid light-matter quasi-particle akin of polaritons composed of an optical soliton trapping a fermionic atom that carries a nontrivial topological quantum number.

Hot carrier generation via plasmon decay is an important mechanism in quantum plasmonics and is typically understood using semiclassical theory however a fully quantum method is required to properly analyse such systems. To this end, the authors develop a quantum-mechanical approach to describe the decay of quantized plasmons into hot electrons and holes.

The effect of localized disruption or failure in interdependent networks with internal community structure remains an open question. Adopting the generating function approach, the authors are able to uncover rich phase transition behaviours and the associated risks for such system, and by studying real networks under random failures within a community, they find that weakening the community strength could rapidly drive the system to a precarious state.

Dynamic light scattering is a method used to examine the dynamics and the size distribution of submicrometer particles and operates in reciprocal space. The authors apply the fundamentals of this technique to magnetic resonance imaging in order to examine particle motion below the spatial resolution in short measurement time.

Fuel cells based on hydrogen combustion are hoped to provide a more environmentally friendly source of energy but still require a lot of development. The authors numerically investigate the physics of pulsating combustion supported by a hydrogen burnt flame.

High-entropy alloys establish a new conceptual framework for alloy design and can exhibit outstanding properties attractive for technological applications. The authors investigate the pressure induced magnetovolume effect in the high-entropy alloy CoCrFeAl and find its origin in two progressive, experimentally tunable magnetic transitions.

Hexagonal boron nitride has been theoretically predicted to have high values for its thermal conductivity which would make it useful for thermal management of devices but these values have not been experimentally achieved. The authors manipulate the isotope concentration of B to increase the thermal conductivity and reach these predicted values.

The energy efficient control of magnetisation for memory applications is one of the most important challenges in the field of spintronics. The authors investigate theoretically the possibility of the switching a one-dimensional antiferromagnet using an external electric field.

Protons can be accelerated up to energies of tens of MeV by having an ultra-intense laser pulse interacting with a solid target, in a mechanism known as Target Normal Sheath Acceleration. The authors show that strong enhancement of proton acceleration and number can be achieved by splitting the laser pulse into two parts of equal energy and opposite incidence angles.

In a society relying on large amount of digital information and big data, information security is of paramount importance. The authors present a concept of physically unclonable function (PUF) based on the randomness of biological systems and offering the potential for a fully unclonable, reproducible and reconfigurable PUF.

Semiconductor microcavities coupled to a quantum well can produce three regimes of coherent light generation depending on the nature of the light–matter and electron–hole interactions. The authors design a Se/Te based microcavity containing a single quantum well which enables them to achieve all three lasing regimes in the one device.