Mar 10 2015
Researchers from the University of Granada and the Massachusetts Institute of Technology (MIT) in collaboration with the Singapore University of Technology and Design have opened the path for the construction of the first symmetry controlled current quantum switch.
Researchers Pablo Ignacio Hurtado (University of Granada) and Daniel Manzano (MIT), the authors of this work.
The manufacturing of this system, which would allow for the control and modification of power currents at atomic level, is still a great challenge for the international scientific community. It could be used, for instance, to build controlled insulating materials, or to design more efficient solar panels (artificial photovoltaic cells) which can optimise the transport of energy and therefore, their efficiency, using symmetry as the basic tool.
This research team, whose work has been published in the prestigious journal Physical Review B of the American Physical Society, is currently working on a realistic design for a quantum switch with these features (i.e. symmetry controlled), based on cold atoms in coherent optical cavities, using microresonators attached to two baths to connect the system with thermic sources at different temperatures. The next step, they claim, is to actually create an experimental symmetry controlled quantum switch based upon this design.
In this research, scientists have described how symmetry, one of the most profound and powerful concepts in theoretical physics, enables the control and manipulation of energy transport in open quantum systems.
Quantum computers
"An open quantum system is nothing but a bunch of atoms or molecules in interaction, subject to the action of an environment that constantly perturbs them. We can currently manipulate with extreme precision these systems, which are the building blocks of the quantum computers of the future", says Pablo Ignacio Hurtado Fernández, a professor at the Electromagnetism and Physics of Materials Department at the University of Granada, the principal investigator in this project.
The 'magic' of quantum systems lies in the fact that, in the presence of a symmetry, an open quantum system can simultaneously work in different stationary states. This research proves that this coexistence of different quantum states is due to the existence of a first order dynamic transition phase, similar to the transition from liquid water to vapour, where both phases (liquid and vapour) coexist simultaneously.
"But there's more: since quantum dynamics is temporarily reversible (i.e. it works in the same way whether it goes 'forwards' or 'backwards'), we have demonstrated that this transition phase is accompanied by its twin, but which manifests itself in very rare fluctuations of the energy current," Hurtado points out. Symmetry induced quantum coexistence allows for the robust storage of multiple coherent quantum states, which opens up many possibilities in quantum computing, according to Daniel Manzano, a researcher at the MIT and co-author of this work.
To conduct the simulations required by this study, researchers have employed the PROTEUS supercomputer, which belongs to the Carlos I Institute of Theoretical and Computational Physics at the University of Granada. PROTEUS is one of the most powerful supercomputers for scientific calculus in the country, with a calculus power of more than 13 TeraFlops, which it can achieve thanks to its 1100 processing nuclei, 2,8 RAM Terabytes and 48 TeraBytes for data storage.
Source: http://www.ugr.es/