tailieunhanh - Advances in Lasers and Electro Optics Part 4

Tham khảo tài liệu 'advances in lasers and electro optics part 4', kỹ thuật - công nghệ, cơ khí - chế tạo máy phục vụ nhu cầu học tập, nghiên cứu và làm việc hiệu quả | 8 Analogue of the Event Horizon in Fibers Friedrich Konig Thomas G. Philbin Chris Kuklewicz Scott Robertson Stephen Hill and Ulf Leonhardt School of Physics and Astronomy University of St Andrews North Haugh St Andrews Fife KY16 9SS United Kingdom 1. Introduction In 1974 Stephen Hawking predicted that gravitational black holes would emit thermal radiation and decay Hawking 1974 . This radiation emitted from an area called the event horizon is since known as Hawking radiation. To date it is still one of the most intriguing physical effects and bears great importance for the development of a quantum theory of gravity cosmology and high energy physics. The Hawking effect is one of a rich class of quantum properties of the vacuum Birrell Davies 1984 Brout et. al. a Milonni 1994 . For example in the Unruh effect Moore 1970 Fulling 1973 Davies 1975 DeWitt 1975 Unruh 1976 an accelerated observer perceives the Minkowski vacuum as a thermal field. The physics of Hawking radiation leaves us with fascinating questions about the laws of nature at transplanckian scales the conservation of information and physics beyond the standard model. Because of the thermal nature of the radiation it is characterized by a temperature the Hawking temperature. For stable astronomical black holes this lies far below the temperature of the cosmic microwave background such that an observation of Hawking radiation in astrophysics seems unlikely. Laboratory analogues of black holes have the potential to make the effect observable Unruh 1981 Schleich Scully 1984 . The space-time geometry of the gravitational field can be represented in coordinates that act as an effective flow Novello et al. 2002 Volovik 2003 Unruh 1981 Jacobson 1991 Rousseaux et al. 2008 . The event horizon lies where the flow velocity appears to exceed the speed of light in vacuum. Analogue systems are thus inspired by the following intuitive idea Unruh 1981 the black hole resembles a river Jacobson 1991 Rousseaux et al. 2008 a .