Final Report Summary - QPQV (Quantum plasmas and the quantum vacuum: New vistas in physics)
In the nano-world, the rules that govern the motion of electrons and atoms are far from what we are used to in from our everyday experience. Empty space, which by its very definition in classical physics constitutes a ‘nothingness’, is a boiling soup of particles and anti-particles coming in and out of existence over extremely short periods of time. The position and motion of quantum particles are only known in a statistical sense, in contrast to our classical world, and knowing e.g. the exact position of a particle makes its velocity completely undetermined. Such strange properties of matter and fields on the smallest scales makes for interesting and important studies given that current state-of-the-art laser systems can produce unprecedented intensities in their focus. The aim of this project is to study the interactions of high-intensity lasers with quantum matter, and moreover to develop models for describing the collective motion of quantum matter.
Within this project we have been able to show that the influence of the quantum vacuum, with its intrinsic fluctuations, could be detected using state-of-the-art high-power laser systems. In particular, the collision of light with light, forbidden in classical physics, has been shown to be possible. Moreover, the fascinating effect named after Unruh, which is closely related to the Hawking effect, in which an observer under acceleration can measure a finite temperature although the temperature is zero in the non-accelerated system, has been shown to be testable using high-intensity laser systems. In the other end of the spectrum, the quantum vacuum can be a source of matter and anti-matter, through a mechanism called the Schwinger process. Such pair production has to be achieved using light intensities well above what we currently can produce. In this project we have investigated if it would be possible to produce pairs from the vacuum using laser fields weaker that a certain critical field, and we have found that it is indeed possible to lower the required laser intensity for pair production, by taking into account e.g. the laser pulse length. The description of a large number of quantum particles interacting with e.g. laser light constitutes a difficult, but important, problem. Within this project we have developed models for describing certain regimes of such interactions, and we have also studied the connection between these models and the corresponding classical models in order to gain deeper understanding about such collective quantum systems. We are currently also using computational techniques for investigating the combination of relativistic, quantum, and collective effects in laser light. These studies are expected to be of great importance for our understanding of the limitations of the next-generation laser systems.
Within this project we have been able to show that the influence of the quantum vacuum, with its intrinsic fluctuations, could be detected using state-of-the-art high-power laser systems. In particular, the collision of light with light, forbidden in classical physics, has been shown to be possible. Moreover, the fascinating effect named after Unruh, which is closely related to the Hawking effect, in which an observer under acceleration can measure a finite temperature although the temperature is zero in the non-accelerated system, has been shown to be testable using high-intensity laser systems. In the other end of the spectrum, the quantum vacuum can be a source of matter and anti-matter, through a mechanism called the Schwinger process. Such pair production has to be achieved using light intensities well above what we currently can produce. In this project we have investigated if it would be possible to produce pairs from the vacuum using laser fields weaker that a certain critical field, and we have found that it is indeed possible to lower the required laser intensity for pair production, by taking into account e.g. the laser pulse length. The description of a large number of quantum particles interacting with e.g. laser light constitutes a difficult, but important, problem. Within this project we have developed models for describing certain regimes of such interactions, and we have also studied the connection between these models and the corresponding classical models in order to gain deeper understanding about such collective quantum systems. We are currently also using computational techniques for investigating the combination of relativistic, quantum, and collective effects in laser light. These studies are expected to be of great importance for our understanding of the limitations of the next-generation laser systems.