Taming the Delayed Choice Quantum Eraser

I discuss the delayed choice quantum eraser experiment (DCQE) by drawing an analogy to a Bell-type measurement and giving a straightforward account in standard quantum mechanics. The delayed choice quantum eraser experiment turns out to resemble a Bell-type scenario in which the paradox's resolution is rather trivial, and so there really is no mystery. At first glance, the experiment suggests that measurements on one part of an entangled photon pair (the idler) can be employed to control whether the measurement outcome of the other part of the photon pair (the signal) produces interference fringes at a screen after being sent through a double slit. Significantly, the choice whether there is interference or not can be made long after the signal photon encounters the screen. The results of the experiment have been alleged to invoke some sort of 'backwards in time influence'. I argue that this issue can be eliminated by taking into proper account the role of the signal photon. Likewise, in the de Broglie-Bohm picture the particle's trajectories can be given a well-defined description at any instant of time during the experiment. Thus, it is again clear that there is no need to resort to any kind of 'backwards in time influence'.Comment: Published version; 19 pages, 4 figure

How to make UK energy policy more predictable again

A series of policy U-turns have made aspects of British energy policy unpredictable. With such reversals having been politically motivated, state involvement must be revisited if the industry is to re-establish its credibility, argues Sam Fankhauser. He explains that making strategy and decision-making more transparent, and delegating regulation to independent bodies, are some steps that will depoliticise the energy sector and increase investor trust

Gravitational redshift, inertia, and the role of charge

I argue that the gravitational redshift effect cannot be explained purely by way of uniformly accelerated frames, as sometimes suggested in the literature. The concepts in need of clarification are spacetime curvature, inertia, and the weak equivalence principle with respect to our understanding of gravitational redshift. Furthermore, I briefly discuss gravitational redshift effects due to charge. Considering charge and mass together seems to give rise to a way of (locally) shielding gravity

Exploring lexical patterns in text : lexical cohesion analysis with WordNet

We present a system for the linguistic exploration and analysis of lexical cohesion in English texts. Using an electronic thesaurus-like resource, Princeton WordNet, and the Brown Corpus of English, we have implemented a process of annotating text with lexical chains and a graphical user interface for inspection of the annotated text. We describe the system and report on some sample linguistic analyses carried out using the combined thesaurus-corpus resource

With or without you? Why the European Union’s climate targets will be harder to meet post-Brexit

The UK has played an important role in shaping and advancing European action on climate change. Without it, other Member States will find themselves picking up the slack or the EU will miss its greenhouse gas target for 2030, write Maria Carvalho and Sam Fankhauser

Shadow on the Plant: A Strategy to Exit.

The light spectrum perceived by plants is affected by crowding, which results in the shade avoidance syndrome (SAS). Findings presented by Pedmale et al. bring cryptochromes to the forefront of SAS and elucidate a fascinating molecular crosstalk between photoreceptor systems operating in different wavebands

Sensing the light environment in plants: photoreceptors and early signaling steps.

Plants must constantly adapt to a changing light environment in order to optimize energy conversion through the process of photosynthesis and to limit photodamage. In addition, plants use light cues for timing of key developmental transitions such as initiation of reproduction (transition to flowering). Plants are equipped with a battery of photoreceptors enabling them to sense a very broad light spectrum spanning from UV-B to far-red wavelength (280-750nm). In this review we briefly describe the different families of plant photosensory receptors and the mechanisms by which they transduce environmental information to influence numerous aspects of plant growth and development throughout their life cycle