University of Southampton

About: University of Southampton is a education organization based out in Southampton, United Kingdom. It is known for research contribution in the topics: Population & Laser. The organization has 37184 authors who have published 99400 publications receiving 3462915 citations. The organization is also known as: Southampton University & Soton Uni.

How General Is Trust in “Most People”? Solving the Radius of Trust Problem

Abstract: Generalized trust has become a paramount topic throughout the social sciences, in its own right and as the key civic component of social capital. To date, cross-national research relies on the stan...

Training Schrödinger’s cat: quantum optimal control

Abstract: It is control that turns scientific knowledge into useful technology: in physics and engineering it provides a systematic way for driving a dynamical system from a given initial state into a desired target state with minimized expenditure of energy and resources As one of the cornerstones for enabling quantum technologies, optimal quantum control keeps evolving and expanding into areas as diverse as quantum-enhanced sensing, manipulation of single spins, photons, or atoms, optical spectroscopy, photochemistry, magnetic resonance (spectroscopy as well as medical imaging), quantum information processing and quantum simulation In this communication, state-of-the-art quantum control techniques are reviewed and put into perspective by a consortium of experts in optimal control theory and applications to spectroscopy, imaging, as well as quantum dynamics of closed and open systems We address key challenges and sketch a roadmap for future developments

Broad line emission from iron K- and L-shell transitions in the active galaxy 1H 0707-495.

Abstract: The emission line arising from a transition of an electron from the iron K shell to the ground state (the K line) is prominent in the reflection spectrum of the hard X-ray continuum irradiating dense accreting matter around a black hole. The corresponding iron L-line emission should be detectable when iron abundance is high. That's the theory, and now broad iron L-line emission has been observed, together with the broad K line in the narrow-line Seyfert galaxy 1H0707. There is a reverberation lag of about 30 s between the direct X-ray continuum and its reflection from matter falling into the hole, a timescale comparable to the light-crossing time of the innermost radii around a supermassive black hole. This discovery opens a window on events close to the black hole event horizon in these objects. Emission arising from a transition of an electron from the iron K shell to the ground state (the K line) is prominent in the reflection spectrum created by the hard X-ray continuum irradiating the dense accreting matter around a black hole. Here the presence of both iron K and L emission is reported in the spectrum of the active galaxy 1H 0707-495. There is a 'reverberation lag' with a timescale comparable to the light-crossing time of the innermost radii around a supermassive black hole. Since the 1995 discovery of the broad iron K-line emission from the Seyfert galaxy MCG–6-30-15 (ref. 1), broad iron K lines have been found in emission from several other Seyfert galaxies2, from accreting stellar-mass black holes3 and even from accreting neutron stars4. The iron K line is prominent in the reflection spectrum5,6 created by the hard-X-ray continuum irradiating dense accreting matter. Relativistic distortion7 of the line makes it sensitive to the strong gravity and spin of the black hole8. The accompanying iron L-line emission should be detectable when the iron abundance is high. Here we report the presence of both iron K and iron L emission in the spectrum of the narrow-line Seyfert 1 galaxy9 1H 0707-495. The bright iron L emission has enabled us to detect a reverberation lag of about 30 s between the direct X-ray continuum and its reflection from matter falling into the black hole. The observed reverberation timescale is comparable to the light-crossing time of the innermost radii around a supermassive black hole. The combination of spectral and timing data on 1H 0707-495 provides strong evidence that we are witnessing emission from matter within a gravitational radius, or a fraction of a light minute, from the event horizon of a rapidly spinning, massive black hole.