## Archive for the ‘particle physics’ category: Page 345

Abstract: In 1959 renowned physicist Richard Feynman, in his talk “Plenty of Room at the Bottom,” spoke of a future in which tiny machines could perform huge feats. Like many forward-looking concepts, his molecule and atom-sized world remained for years in the realm of science fiction.

And then, scientists and other creative thinkers began to realize Feynman’s nanotechnological visions.

In the spirit of Feynman’s insight, and in response to the challenges he issued as a way to inspire scientific and engineering creativity, electrical and computer engineers at UC Santa Barbara have developed a design for a functional nanoscale computing device. The concept involves a dense, three-dimensional circuit operating on an unconventional type of logic that could, theoretically, be packed into a block no bigger than 50 nanometers on any side.

Quantum theory is strange and counterintuitive, but it’s very precise. Lots of analogies and broad concepts are presented in popular science trying to give an accurate description of quantum behavior, but if you really want to understand how quantum theory (or any other theory) works, you need to look at the mathematical details. It’s only the mathematics that shows us what’s truly going on.

Mathematically, a quantum object is described by a function of complex numbers governed by the Schrödinger equation. This function is known as the wavefunction, and it allows you to determine quantum behavior. The wavefunction represents the state of the system, which tells you the probability of various outcomes to a particular experiment (observation). To find the probability, you simply multiply the wavefunction by its complex conjugate. This is how quantum objects can have wavelike properties (the wavefunction) and particle properties (the probable outcome).

No, wait. Actually a quantum object is described by a mathematical quantity known as a matrix. As Werner Heisenberg showed, each type of quantity you could observe (position, momentum, energy) is represented by a matrix as well (known as an operator). By multiplying the operator and the quantum state matrix in a particular way, you get the probability of a particular outcome. The wavelike behavior is a result of the multiple connections between states within the matrix.

In Brief:

• 80 years after it was first theorized, researchers have found more evidence for the existence of a fermion that’s its own antiparticle.
• The discovery of Majorana fermions could be the key to developing usable quantum computers.

Robert Wolkow, University of Alberta physics professor and the Principal Research Officer at Canada’s National Institute for Nanotechnology, has developed a technique to switch a single-atom channel.

Just WOW!

PULLMAN, Wash., Oct. 26 — Washington State University and NASA scientists are set to begin an investigation into the strange world of quantum physics on the International Space Station.

WSU physicists Peter Engels and Maren Mossman are part of a team studying the behavior of atoms laser-cooled to temperatures just a few billionths of a degree above absolute zero, the point where they behave like one wave of discrete particles.

Drug discovery is a long and difficult process that requires a comprehensive understanding of the molecular structures of compounds under investigation. It’s difficult to have an idea of the precise shape of complex molecules such as proteins, but researchers at University of Melbourne in Australia have come up with a way of seeing the location of individual atoms within biomolecules.

Using quantum bits, most notably utilized in quantum computer research, the investigators offer a way of producing a magnetic resonance sensor and a magnetic field gradient that can work as a tiny MRI machine. The machine would have the resolution capable of seeing single atoms components of larger molecules. This MRI machine has yet to be actually built, but the steps have been laid out based on comprehensive theoretical work. If it proves successful in practice, the technology may overcome current imaging techniques that rely on statistical averages and don’t work well on molecules that don’t crystallize well.

“In a conventional MRI machine large magnets set up a field gradient in all three directions to create 3D images; in our system we use the natural magnetic properties of a single atomic qubit,” said lead author of the research Viktor Perunicic. “The system would be fabricated on-chip, and by carefully controlling the quantum state of the qubit probe as it interacts with the atoms in the target molecule, we can extract information about the positions of atoms by periodically measuring the qubit probe and thus create an image of the molecule’s structure.”

Using ultrafast laser flashes, physicists from the Max Planck Institute have generated the fastest electric current that has ever been measured inside a solid material.

In the field of electronics, the principle ‘the smaller, the better’ applies. Some building blocks of computers or mobile phones, however, have become nearly as small today as only a few atoms. It is therefore hardly possible to reduce them any further.

Another factor for the performance of electronic devices is the speed at which electric currents oscillate. Scientists at the Max Planck Institute of Quantum Optics have now created electric currents inside solids which exceed the frequency of visible light by more than ten times They made electrons in silicon dioxide oscillate with ultrafast laser pulses. The conductivity of the material which is typically used as an insulator was increased by more than 19 orders of magnitude.

Oh boy!

Space vacuum that appears to be stable due to the complete absence of substance in it, is likely to be fraught with great danger. The idea about the destruction of the universe is based on the hypothesis of vacuum instability. Any system in our world has a certain amount of potential energy. But, space vacuum is not as empty as it may seem to be. Vacuum in space is filled with quantum particles, which, in turn, may seek their own “stability” to annihilate the material world in its entirety during the process.

The Large Electron-Positron collider returns to haunt the LHC.