Tag Archives: quantum computing

Physicists Discover New Massless Particle; Could Revolutionize Electronics & Quantum Computing

Hasan massless particle

Physics may have just taken a new leap forward, as three independent groups of physicists have found strong evidence for massless particles called “Weyl fermions,” which exist as quasiparticles – collective excitations of electrons. Ultimately, this discovery is over 80 years in the making, dating back to Paul Dirac.

In 1928, Dirac came up with an equation that described the spin of fermions (fermions are the building blocks that make up all matter). Within his equation, he discovered that, in relation to particles that have charge and mass, there should be a another particle and antiparticle—what we know as the electron and (its antiparticle) the positron.

Yet, there are more than one ways to skin a cat.

Other solutions to this equation hinted at more exotic kinds of particles. Enter Hermann Weyl, a German mathematician who, in 1929, come up with a solution that involved massless particles. These became known as “Weyl fermions.” And, for a number of years, physicists believed that neutrinos (subatomic particles that are produced by the decay of radioactive elements) were actually Weyl particles. Yet, further studies, which were published in 1998, indicated that neutrinos do, in fact, have mass, which means that they cannot be the aforementioned Weyl particles.

But now, we have evidence that Weyl fermions actually exist.

Unlocking the Find

The research comes thanks to Zahid Hasan over at Princeton University, who uncovered these particles in the semimetal tanatalum arsenide (which is referred to as TaAs). Hasan and his team suggested that  TaAs should contain Weyl fermions and (here is the important bit) it should have what is known as a “Fermi arc.” And in 2014, the team found evidence of such an arc.

Artist's rendition via ChutterStock

But that’s not all, another team, led by Hongming Weng at the Chinese Academy of Sciences, found similar evidence in an independent study that used the same methods. And Marin Soljačić and colleagues (hailing from MIT and the Univeristy of China) have seen evidence of Weyl fermions in a different material, specifically, a “double-gyroid” photonic crystal.

In this latter case, the team fired microwaves at the crystal and measured microwave transmission through it, varying the frequency of the microwaves throughout the experiment. Through this process, the team could map the structure of the crystal, allowing them to determine which microwave frequencies can travel through the crystal and which cannot. In the end, this revealed the presence of “Weyl points” in the structure, which is strong evidence for Weyl fermion states existing within the photonic crystal.

The Future of Physics

The significance of this find, quite literally, cannot be overstated. Hasan is clear to point this out, noting in the press release that, “The physics of the Weyl fermion are so strange, there could be many things that arise from this particle that we’re just not capable of imagining now.”

He goes on to note more specific applications: “It’s like they have their own GPS and steer themselves without scattering. They will move and move only in one direction since they are either right-handed or left-handed and never come to an end because they just tunnel through. These are very fast electrons that behave like unidirectional light beams and can be used for new types of quantum computing.” Soljačić, the head of the second study, adds that, “The discovery of Weyl points is not only the smoking gun to a scientific mystery, it paves the way to absolutely new photonic phenomena and applications.”

Ultimately, it is believed Weyl fermions could be very useful, in that, because they are massless, they can conduct electric charge much faster than normal electrons. Admittedly, this same feature is exhibited by electrons in graphene. Yet, graphene is a 2D material, Weyl fermions are thought to exist in more practical 3D materials.

1 Comment

Filed under Uncategorized

MIT, Harvard scientists accidentally create real-life lightsaber

MIT, Harvard scientists accidentally create real-life lightsaber

Published September 29, 2013

  • Star Wars Light Saber Fight

    Luke Skywalker engages in a perilous lightsaber duel with Darth Vader in ‘Star Wars: Episode V The Empire Strikes Back.’ (LUCAS FILMS/ZUMA PRESS)

The force is clearly with them.

In a reported first, researchers at Harvard and the Massachusetts Institute of Technology have developed a newfangled technology that theoretically could be used to construct an actual lightsaber.

Until now, photons, or the mass-less particles that constitute light, were thought to not interact, but rather simply pass through each other, just two beams of luminescence during a laser-light show.

“The physics of what’s happening in these molecules is similar to what we see in the movies.”

– Mikhail Lukin, Harvard physics professor 

But according to the Harvard Gazette, scientists at the Harvard-MIT Center for Ultracold Atoms have improbably coaxed photons into hardened molecules you could, in fact, whack against each other in, say, a Bespin-based duel-to-the-death resulting in one person, sadly, losing a hand.

As a lightsaber-wielding Darth Vader once notably noted, “Don’t make me destroy you . . .”

“It’s not an inapt analogy to compare this to lightsabers,” Harvard professor of physics Mikhail Lukin told the Gazette.

“When these photons interact with each other, they’re pushing against and deflecting each other. The physics of what’s happening in these molecules is similar to what we see in the movies.”

Added MIT Professor of Physics Vladan Vuletic in an interview with WBZ-TV, “It has long been a dream to have photons of light beams interact with one another. . .We use laser beams and shine them in from six sides and these laser beams actually cool the atoms.

“Maybe a characteristic of a lightsaber is that you have these two light beams and they don’t go through each other as you might expect; they just kind of bounce off each other.”

However, don’t expect the new technology to soon result in a real-life, proverbial “elegant weapon for a more civilized age,” as exiled Jedi Obi-Wan Kenobe once put it.

Instead, the science behind the recent breakthrough will likely lead researchers to realizing the till-now coveted concept of quantum computing.

“What it will be useful for we don’t know yet,” Lukin reportedly said. “But it’s a new state of matter, so we are hopeful that new applications may emerge as we continue to investigate these photonic molecules’ properties.”

Now, if science would only allow the would-be smugglers out there to get their hands on a trusty blaster.

1 Comment

Filed under Humor and Observations