Proceedings A publishes articles across the chemical, computational, Earth, engineering, mathematical, and physical sciences. The journal publishes research papers, as well as short reviews containing original and interesting new ideas. The articles published are high-quality, original, fundamental articles of interest to a wide range of scientists, and often have long citation half-lives. As well as established disciplines, we encourage emerging and interdisciplinary areas.

### Small entropy changes allow quantum measurements to be nearly reversed

(Phys.org)—In 1975, Swedish physicist Göran Lindblad developed a theorem that describes the change in entropy that occurs during a quantum measurement. Today, this theorem is a foundational component of quantum information ...

### Grasshopper problem yields insight into quantum theory

(Phys.org)—Like many mathematical puzzles, the grasshopper problem is simple to state but difficult to solve: A grasshopper lands at a random point on a lawn of area 1, then jumps once, a fixed distance, in a random direction. ...

### Doing without dark energy: Mathematicians propose alternative explanation for cosmic acceleration

Three mathematicians have a different explanation for the accelerating expansion of the universe that does without theories of "dark energy." Einstein's original equations for General Relativity actually predict cosmic acceleration ...

### Two-ball bounce problem explained

Researchers from the University of Bristol have revisited a well-known classroom demonstration where a lighter ball is dropped on top of a larger heavier ball and offer a model to explain the phenomenon.

### New technology could reduce wind energy costs

Engineers from the University of Sheffield have developed a novel technique to predict when bearings inside wind turbines will fail which could make wind energy cheaper.

### Why too much evidence can be a bad thing

(Phys.org)—Under ancient Jewish law, if a suspect on trial was unanimously found guilty by all judges, then the suspect was acquitted. This reasoning sounds counterintuitive, but the legislators of the time had noticed ...

### How close to invisible can a mirror be?

(Phys.org)—In 2011, mathematicians Alexander Plakhov and Vera Roshchina proved that objects with mirror surfaces cannot be perfectly invisible. Now in a new study, Plakhov has returned to the problem, asking just how close ...

### Physicists provide support for retrocausal quantum theory, in which the future influences the past

(Phys.org)—Although there are many counterintuitive ideas in quantum theory, the idea that influences can travel backwards in time (from the future to the past) is generally not one of them. However, recently some physicists ...

### How to cut your lawn for grasshoppers

Picture a grasshopper landing randomly on a lawn of fixed area. If it then jumps a certain distance in a random direction, what shape should the lawn be to maximise the chance that the grasshopper stays on the lawn after ...

### A non-probabilistic quantum theory produces unpredictable results

(Phys.org)—Quantum measurements are often inherently unpredictable, yet the usual way in which quantum theory accounts for unpredictability has long been viewed as somewhat unsatisfactory. In a new study, University of ...