[ad_1]
Researchers from the Ames Laboratory, Brookhaven National Laboratory and the University of Alabama at Birmingham have identified a light-induced switching mechanism in a Dirac semi-metal.
The mechanism offers a new technique for manipulating topological material, triggered by the movement of electrons and atoms, that will allow quantum computation and a topological transistor using light waves.
Much like the way that existing photodiodes and transistors replaced vacuum tubes more than five decades ago, researchers are looking for an analogous leap in novel materials and design principles to realize quantum computing capabilities.
Today’s computing power faces enormous difficulties with respect to power, speed consumption and complexity. Considerable progress is required to overcome the physical limits reached as the chips and electronics heat up and become faster. Specifically, at small scales, these problems have turned out to be the main barriers to improving performance.
Topological light wave engineering seeks to overcome all of these challenges by driving quantum periodic motion to guide electrons and atoms through new degrees of freedom, i.e. topology, and induce transitions without heating at unprecedented terahertz frequencies, defined as a trillion cycles per second, clock rates.
Jigang Wang, Senior Scientist, Ames Laboratory
Wang, who is also a professor of physics at Iowa State University, added: “This new consistent control principle is in stark contrast to any equilibrium adjustment method used so far, such as deformation, magnetic and electric fields, which have much slower speeds and higher energy losses.. “
The large-scale application of new computational principles, such as quantum computing, requires the development of devices in which fragile quantum states are protected against their noisy environments. One method is to develop topological quantum computation where qubits are based on “symmetrically protected” quasiparticles that are unaffected by noise.
But researchers investigating these topological materials face difficulties: how to find and control these unique quantum behaviors so that applications like quantum computing are feasible.
As part of the experiment, Wang and his team showcased how to achieve control by using light to drive quantum states in a Dirac semi-metal, an exotic material that exhibits extreme sensitivity due to its proximity to a wide range of topological phases.
We accomplish this by applying a new principle of quantum light control known as mode-selective Raman phonon coherent oscillations: driving periodic movements of atoms over the equilibrium position using short pulses of light. These driven quantum fluctuations induce transitions between electronic states with different gaps and topological orders..
Ilias Perakis, Professor of Physics and Professor, University of Alabama at Birmingham
Such an analog to dynamic shift is the periodically steered Kapitza pendulum, which can shift to an inverted but stable position by applying high-frequency vibration. The study demonstrates that this classical control principle (steering materials toward a new stable condition that is not common) is remarkably applicable to a broader range of quantum phase transitions and topological phases.
Our work opens a new arena of topological electronics for light waves and phase transitions controlled by quantum coherence. This will be useful in developing future high-speed, low-power electronic and quantum computing strategies..
Qiang Li, Group Leader, Advanced Energy Materials Group, Brookhaven National Laboratory
Spectroscopy and data analysis were carried out at the Ames Laboratory. Model development and analysis were conducted, in part, at the University of Alabama at Birmingham. Sample development and magneto-transport measurements were carried out at the Brookhaven National Laboratory.
The Center for the Advancement of Topological Semimetals, a DOE Energy Frontier Research Center at the Ames Laboratory, supported functional density calculations.
Further discussion of the study was reported in the paper “Light-Driven Raman Coherence as a Non-Thermal Path to Ultrafast Topology Switching in a Dirac Semi-Metal”, which was published in Physical Review X and written by C. Vaswani, L.-L. Wang, D.H. Mudensenselage, Q. Li, P. M. Lozano, G. Gu, D. Cheng, B. Song, L. Luo, R. H. J. Kim, C. Huang, Z. Liu, M. Mootz, I.E. Perakis, Y. Yao, K. M. Ho and J. Wang.
Source: https://www.ameslab.gov/
