Items tagged with "optical lattice"
Inside a material, such as an insulator, semiconductor or superconductor, a complex drama unfolds that determines the physical properties. Physicists work to observe these scenes and recreate the script that the actors—electrons, atoms and other particles—play out. It is no surprise that electrons are most frequently the stars in the stories behind electrical properties. But there is an important supporting actor that usually doesn’t get a fair share of the limelight.
Exotic physics can happen when quantum particles come together and talk to each other. Understanding such processes is challenging for scientists, because the particle interactions can be hard to glimpse and even harder to control. Moreover, modern computer simulations struggle to make sense of all the intricate dynamics going on in a large group of particles. Luckily, atoms cooled to near zero temperatures can provide insight into this problem.
For scientists investigating the behavior of cold atoms trapped in a web of interfering lasers, two kinds of atoms can be better than one. The second species allows researchers to study more complex dynamics, like how the interactions between atoms caught in a 3-D lattice can form molecules stationed at the same site.
Physicists use theoretical and experimental techniques to develop explanations of the goings-on in nature. Somewhat surprisingly, many phenomena such as electrical conduction can be explained through relatively simplified mathematical pictures — models that were constructed well before the advent of modern computation. And then there are things in nature that push even the limits of high performance computing and sophisticated experimental tools.
Quantum computers will someday perform calculations impossible for conventional digital computers. But for that to happen, the core quantum information must be preserved against contamination from the environment. In other words, decoherence of qubits must be forestalled. Coherence, the ability of a system to retain quantum integrity---meaning that one part of the system can be used to predict the behavior of other parts---is an important consideration.
An optical lattice is formed by the intersection of multiple laser beams, producing a standing wave pattern. Within that pattern, as the beams interact with each other, there are regions with higher and lower light intensity. An atom placed in the lattice will naturally tend to seek the minimal or maximal intensity points depending on the laser frequency with respect to the atom's internal state. Because lattice configurations resemble the geometrical arrangements of atoms in crystalline solids, they can be used to study atomic behaviors in a highly controlled environment.