Robert P. Crease enjoys Sean Carroll’s foray into a 60-year-old theory.
Quantum gauge theories are mathematical constructs that are typically used by physicists to describe subatomic particles, their associated wave fields and the interactions between them. The dynamics outlined by these theories are difficult to compute, yet effectively emulating them in the lab could lead to valuable new insight and discoveries.
In a recent study, a team of researchers at ETH Zurich’s Institute for Quantum Electronics successfully implemented a fundamental ingredient for the simulation of quantum gauge theories in a laboratory experiment. Their hope is that by simulating quantum systems in a highly controlled environment, they will gather interesting observations and broaden their understanding of many-body systems (i.e., systems with many particles that interact with each other).
“Usually, our work is inspired by phenomena in solid state physics such as strongly correlated phases of electrons in complex materials,” Tilman Esslinger, one of the researchers who carried out the study, told Phys.org. “In our current work, however, we wanted to extend the scope of our experimental platform (i.e., ultracold atoms in optical lattices) in order to investigate a new set of phenomena occurring in high-energy and condensed matter physics. The objective was to demonstrate that it is possible to engineer gauge fields in our setup that are dynamical quantum degrees of freedom due to their coupling to a matter field.”
Quantum information relies on the possibility of writing messages in a quantum particle and reading them out in a reliable way. If, however, the particle is relativistic, meaning that it moves with velocities close to the speed of light, it is impossible for standard techniques to decode the message unambiguously, and the communication therefore fails.
Thanks to the introduction of a new method, researchers at the University of Vienna and the Austrian Academy of Sciences have developed reliable decoding of quantum messages transmitted at extremely high speeds. The results, published in the journal Physical Review Letters, opens up new possibilities of technological applications in quantum information and quantum communication.
Imagine the following situation: Anna and Bill want to exchange a message by using a property of a quantum particle, say the spin of an electron, which is an intrinsic form of particle’s rotation. Bill needs Anna’s message as quickly as possible, so Anna has to send the electron at maximum speed, very close to the speed of light. Given that Anna has the electron in her laboratory localized, the Heisenberg uncertainty principle forbids the velocity of the electron to be defined with arbitrary precision. When the electron travels at extremely high speed, the interplay between special relativity and quantum physics causes the spin and the velocity of the electron to become entangled. Due to this correlation, which is stronger than what is classically possible, Bill is not able to read out the spin with the standard method. Can Anna and Bill improve their communication strategy?
The theories of quantum mechanics and gravity are notorious for being incompatible, despite the efforts of scores of physicists over the past fifty years. However, recently an international team of researchers led by physicists from the University of Vienna, the Austrian Academy of Sciences as well as the University of Queensland (AUS) and the Stevens Institute of Technology (U.S.) have combined the key elements of the two theories describing the flow of time and discovered that temporal order between events can exhibit genuine quantum features.
According to general relativity, the presence of a massive object slows down the flow of time. This means that a clock placed close to a massive object will run slower as compared to an identical one that is further away.
However, the rules of quantum theory allow for any object to be prepared in a superposition state. A superposition state of two locations is different to placing an object in one or the other location randomly—it is another way for an object to exist, allowed by the laws of quantum physics.
Shouldn’t the title just be “Engineer”? What an amazing product!
Roy Allela, a 25-year old engineer and inventor from Kenya, has found the ultimate solution to bridging the communication barrier between deaf and hearing people. He has invented the Sign-IO gloves that can translate signed hand movements to audible speech so deaf people can “talk” even to those who don’t understand sign language.
The Sign-IO gloves feature sensors mounted on each of the five fingers to determine its movements, including how much a finger is bent. The gloves are connected via Bluetooth to an Android app that Allela also invented which uses a text-to-speech function to convert the gestures to vocal speech.
Allela was inspired to create the gloves because he and his family struggled to communicate with his 6-year-old niece who was born deaf. “My niece wears the gloves, pairs them to her phone or mine, then starts signing and I’m able to understand what she’s saying. Like all sign language users, she’s very good at lip reading, so she doesn’t need me to sign back,” he said in an interview with The Guardian.
Dark energy may not exist
Posted in cosmology
Research finds a possible explanation for accelerating cosmic expansion that challenges standard cosmological models. Stuart Gary reports.
Circa 1997
By Michio Kaku
IS THERE a Final Theory in physics? Will we one day have a complete theory that will explain everything from subatomic particles, atoms and supernovae to the big bang? Einstein spent the last 30 years of his life in a fruitless quest for the fabled unified field theory. His approach has since been written off as futile.
In the 1980s, attention switched to superstring theory as the leading candidate for a final theory. This revolution began when physicists realised that the subatomic particles found in nature, such as electrons and quarks, may not be particles at all, but tiny vibrating strings.
Ebook written by Lárus Thorlacius, Thordur Jonsson. Read this book using Google Play Books app on your PC, android, iOS devices. Download for offline reading, highlight, bookmark or take notes while you read M-Theory and Quantum Geometry.
“Over decades, both military and space programs all around the world have known the negative impact of radiation on semiconductor-based electronics,” says Meyya Meyyappan, Chief Scientist for Exploration Technology at the Center for Nanotechnology, at NASA’s Ames Research Center. What has changed with the push towards nanoscale feature sizes is that terrestrial levels of radiation can now also cause problems that had previously primarily concerned applications in space and defence. Packaging contaminants can cause alpha radiation that create rogue electron-hole pairs, and even the ambient terrestrial neutron flux at sea level – around 20 cm−2 h−1 – can have adverse implications for nanoscale devices.
Fortunately work to produce radiation-hardy electronics has been underway for some time at NASA, where space mission electronics are particularly prone to radiation exposure and cumbersome radiation shielding comes with a particularly costly load penalty. Vacuum electronics systems, the precursors to today’s silicon world, are actually immune to radiation damage. Alongside Jin-Woo Han and colleagues Myeong-Lok Seol, Dong-Il Moon and Gary Hunter at Ames and NASA’s Glenn Research Centre, Meyyappan has been working towards a renaissance of the old technology with a nano makeover.
In a recent Nature Electronics article, they report how with device structure innovations and a new material platform they can demonstrate nanoscale vacuum channel transistors that compete with solid-state system responses while proving impervious to radiation exposure.