Skip to main content

Amazing quantum world

Simulating the behavior of a single particle can be quite a challenging task in physics; after all, it is microscopic and we usually cannot watch in real time. It becomes even more complicated when you realize that the particle has to follow the laws of quantum physics, which allow it be in two or more places at the same time through a phenomenon called superposition. Understanding how a quantum particle behaves is necessary to enhance our fundamental understanding of the laws of physics. Dr. C. M. Chandrashekar, a post-doctoral researcher in Professor Thomas Busch's Quantum Systems Unit at the Okinawa Institute of Science and Technology Graduate University, is running simulations and carrying out analytical studies to understand how single quantum particles travel.
The first step to simulating quantum physics is to find the very basic rules that govern the motion of the quantum particle and then add complexity step by step. In Dr. Chandrashekar's work, a particle is traveling along a lattice, a defined set of paths that looks like a city grid. As the particle travels forward, it approaches a junction where it can go right or left. But under the rules of quantum mechanics, the particle does not have to choose, so can follow both directions and end up in two places at once. The particle's path begins to look like a branching web, with some paths leading to distant points on the lattice and other paths overlapping and ending on the same point. Paths that lead to the same point can cancel each other, known as destructive interference, or add up known as constructive interference. This movement, where the particle moves and encounters interferences, is known amongst physicists as a quantum walk. At the end of the simulation, Dr. Chandrashekar combines the data into a probability distribution, a graph that represents the probability that a particle is at each point on the lattice at a one moment in time.
Chandrashekar has simulated quantum particles traveling on different grids and has analyzed the probability distributions for each one. His special interest is in more complicated lattices, which contain broken junctions where the particle can no longer proceed. For each simulation, Chandrashekar found a way to mathematically describe the dynamics of the particle and find the corresponding probability distribution. "There's a strong probability of the particle being around one location, despite it having the possibility to be anywhere" Chandrashekar said, "and it is quantum interference that is causing that." Having a model for this process also means that he can reverse the walk; that is, he can work backwards from the probability distribution to predict the initial position of the particle and the way it has moved.
"Any discrete space is like a lattice," Chandrashekar said, "but often they are rather complex." Any continuous space can be mapped onto fragments in order to be simplified. Then, Chandrashekar can make the gaps between fragments infinitely small and perform the simulation again. "At the end we let the gap between the fragments go to zero," Chandrashekar says, "and you have a continuous space back."
Understanding the motion of a quantum particle has a broad range of impacts. It will help to advance ideas in quantum computing, allowing computers to store and process more information using the same amount of memory and power. It will help understand fundamental transport processes for electrons or energy in complex systems. The simulations using a hexagonal lattice illuminate parts of nanoscience, such as carbon nanotube designers who rely on graphene's hexagonal structure. "You see certain observations and you ask, 'What led to this?'" Chandrashekar says. "Quantum walks might be responsible for some processes we have not yet understood."

Labels:

Comments

Post a Comment

Popular posts from this blog

Nano thin film Barium Stannate :New revolution to electronics and solar industry

A team of researchers, led by the University of Minnesota, have discovered a new nano-scale thin film material with the highest-ever conductivity in its class. The new material could lead to smaller, faster, and more powerful electronics, as well as more efficient solar cells. The discovery is being published today in  Nature Communications , an open access journal that publishes high-quality research from all areas of the natural sciences. Researchers say that what makes this new material so unique is that it has a high conductivity, which helps electronics conduct more electricity and become more powerful. But the material also has a wide bandgap, which means light can easily pass through the material making it optically transparent. In most cases, materials with wide bandgap, usually have either low conductivity or poor transparency. "The high conductivity and wide bandgap make this an ideal material for making optically transparent conducting films which could be used...
Post a Comment
Read more

Transition metal dichalcogenides (TMDs): a new revolution to quantum technologies

Transition metal dichalcogenides (TMDs) are layered semiconductors that can be exfoliated into layers only a few atoms thick. Recent research has shown that some TMDs can contain quantum light sources that can emit single photons of light. Until now, the occurrence of these quantum light emitters has been random. Now, researchers in the Graphene Flagship working at the University of Cambridge, UK, have created large scale arrays of these quantum emitters in different TMD materials. The work, also involving researchers from Harvard University, US, is published in  Nature Communications . This new approach leads to large quantities of on-demand, single photon emitters, paving the way for integrating ultra-thin, single photons in electronic devices. Quantum light emitters, or quantum dots, are of interest for many different applications, including quantum communication and networks. Until now, it has been very difficult to produce large arrays of quantum emitters close together w...
Post a Comment
Read more

Building blocks of nanoelectronics

The team of researchers headed by Prof. Dr. Sabine Maier, Prof. Dr. Milan Kivala and Prof. Dr. Andreas Görling has successfully assembled and tested conductors and networks made up of individual, newly developed building block molecules. These could in future serve as the basis of components for optoelectronic systems, such as flexible flat screens or sensors. The FAU researchers have published their results in the journal  Nature Communications . Lithographic techniques in which the required structures are cut from existing blocks are mainly employed at present to produce micro- and nano-electronic components. 'This is not unlike how a sculptor creates an object from existing material by cutting away what they do not need. How small we can make these structures is determined by the quality of the material and our mechanical skills,' explains Prof. Dr. Sabine Maier from the Chair of Experimental Physics. "We now have something like a set of Lego bricks for use in the ...
Post a Comment
Read more