Potential technology for quantum computing, keener sensors
Researchers at Case Western Reserve University have developed a way to swiftly and precisely control electron spins at room temperature.
The technology, described in Nature Communications, offers a possible alternative strategy for building quantum computers that are far faster and more powerful than today's supercomputers.
"What makes electronic devices possible is controlling the movement of electrons from place to place using electric fields that are strong, fast and local," said physics Professor Jesse Berezovsky, leader of the research. "That's hard with magnetic fields, but they're what you need to control spin."
Other researchers have searched for materials where electric fields can mimic the effects of a magnetic field, but finding materials where this effect is strong enough and still works at room temperature has proven difficult.
"Our solution," Berezovsky said, "is to use a magnetic vortex."
Berezovsky worked with physics PhD students Michael S. Wolf and Robert Badea.
The researchers fabricated magnetic micro-disks that have no north and south poles like those on a bar magnet, but magnetize into a vortex. A magnetic field emanates from the vortex core. At the center point, the field is particularly strong and rises perpendicular to the disk.
The vortices are coupled with diamond nanoparticles. In the diamond lattice inside each nanoparticle, several individual spins are trapped inside of defects called nitrogen vacancies.
The scientists use a pulse from a laser to initialize the spin. By applying microwaves and a weak magnetic field, Berezovsky's team can move the vortex in nanoseconds, shifting the central point, which can cause an electron to change its spin.
In what's called a quantum coherent state, the spin can act as a quantum bit, or qubit--the basic unit of information in a quantum computer,
In current computers, bits of information exist in one of two states: zero or one. But in a superposition state, the spin can be up and down at the same time, that is, zero and one simultaneously. That capability would allow for more complex and faster computing.
"The spins are close to each other; you want spins to interact with their neighbors in quantum computing," Berezovsky said. "The power comes from entanglement."
The magnetic field gradient produced by a vortex proved sufficient to manipulate spins just nanometers apart.
In addition to computing, electrons controlled in coherent quantum states might be useful for extremely high-resolution sensors, the researchers say. For example, in an MRI, they could be used to sense magnetic fields in far more detail than with today's technology, perhaps distinguishing atoms.
Controlling the electron spins without destroying the coherent quantum states has proven difficult with other techniques, but a series of experiments by the group has shown the quantum states remain solid. In fact, "the vortex appears to enhance the microwave field we apply," Berezovsky said.
The scientists are continuing to shorten the time it takes to change the spin, which is a key to high-speed computing. They are also investigating the interactions between the vortex, microwave magnetic field and electron spin, and how they evolve together.
Kevin Mayhood | EurekAlert!
MEMS chips get metatlenses
21.02.2018 | American Institute of Physics
International team publishes roadmap to enhance radioresistance for space colonization
21.02.2018 | Biogerontology Research Foundation
For the first time, a team of researchers at the Max-Planck Institute (MPI) for Polymer Research in Mainz, Germany, has succeeded in making an integrated circuit (IC) from just a monolayer of a semiconducting polymer via a bottom-up, self-assembly approach.
In the self-assembly process, the semiconducting polymer arranges itself into an ordered monolayer in a transistor. The transistors are binary switches used...
Breakthrough provides a new concept of the design of molecular motors, sensors and electricity generators at nanoscale
Researchers from the Institute of Organic Chemistry and Biochemistry of the CAS (IOCB Prague), Institute of Physics of the CAS (IP CAS) and Palacký University...
For photographers and scientists, lenses are lifesavers. They reflect and refract light, making possible the imaging systems that drive discovery through the microscope and preserve history through cameras.
But today's glass-based lenses are bulky and resist miniaturization. Next-generation technologies, such as ultrathin cameras or tiny microscopes, require...
Scientists from the University of Zurich have succeeded for the first time in tracking individual stem cells and their neuronal progeny over months within the intact adult brain. This study sheds light on how new neurons are produced throughout life.
The generation of new nerve cells was once thought to taper off at the end of embryonic development. However, recent research has shown that the adult brain...
Theoretical physicists propose to use negative interference to control heat flow in quantum devices. Study published in Physical Review Letters
Quantum computer parts are sensitive and need to be cooled to very low temperatures. Their tiny size makes them particularly susceptible to a temperature...
15.02.2018 | Event News
13.02.2018 | Event News
12.02.2018 | Event News
21.02.2018 | Materials Sciences
21.02.2018 | Health and Medicine
21.02.2018 | Physics and Astronomy