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Category: particle physics – Page 661

Oxford team demonstrates ‘hybrid’ logic gate as work towards quantum computer continues

‘In a nice piece of “spin-off science” from this technological achievement, we were able to perform a “Bell test”, by first using the high-precision logic gate to generate an entangled state of the two different-species ions, then manipulating and measuring them independently. This is a test which probes the non-local nature of quantum mechanics; that is, the fact that an entangled state of two separated particles has properties that cannot be mimicked by a classical system. This was the first time such a test had been performed on two different species of atom separated by many times the atomic size.’

While Professor Lucas cautions that the so-called ‘locality loophole’ is still present in this experiment, there is no doubt the work is an important contribution to the growing body of research exploring the physics of entanglement. He says: ‘The significance of the work for trapped-ion quantum computing is that we show that quantum logic gates between different isotopic species are possible, can be driven by a relatively simple laser system, and can work with precision beyond the so-called “fault-tolerant threshold” precision of approximately 99% — the precision necessary to implement the techniques of quantum error correction, without which a quantum computer of useful size cannot be built.’

In the long term, it is likely that different atomic elements will be required, rather than different isotopes. In closely related work published in the same issue of Nature, by Ting Rei Tan et al, the NIST Ion Storage group has demonstrated a different type of quantum logic gate using ions of two different elements (beryllium and magnesium).

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Scientists have built a functional ‘hybrid’ logic gate for use in quantum computers

As conventional computers draw ever closer to their theoretical limit, the race is on to build a machine that can truly harness the unprecedented processing power of quantum computing. And now two research teams have independently demonstrated how entangling atoms from different elements can address the problem of quantum memory errors while functioning within a logic gate framework, and also pass the all-important test of true entanglement.

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China’s dark-matter satellite launches era of space science

“The detector could help to clear up some mysteries. In 2013, the AMS announced it had seen hints of dark matter but so far it has detected too few high-energy particles to say for sure. Though DAMPE lacks the equipment to resolve the conundrum directly, it could reveal if the signal is caused by a different astrophysical source, such as pulsars, says Capell.

Although it will collect fewer incoming photons, DAMPE is better at pinpointing their energy than are existing γ-ray telescopes, such as NASA’s Fermi-LAT, says Miguel Sanchez-Conde, a physicist at the Oskar Klein Centre for Cosmoparticle Physics in Stockholm. This capability should allow DAMPE to see sharp spikes in radiation predicted by some dark-matter models.”

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Team adds to quantum computing toolkit with mixed-atom logic operations

Physicists at the National Institute of Standards and Technology (NIST) have added to their collection of ingredients for future quantum computers by performing logic operations—basic computing steps—with two atoms of different elements. This hybrid design could be an advantage in large computers and networks based on quantum physics.

The NIST experiment, described in the Dec. 17 issue of Nature, manipulated one magnesium and one beryllium ion (charged atom) confined in a custom trap (see photo). The scientists used two sets of laser beams to entangle the two ions—establishing a special quantum link between their properties—and to perform two types of logic operations, a controlled NOT (CNOT) gate and a SWAP gate. The same issue of Nature describes similar work with two forms of performed at the University of Oxford.

“Hybrid quantum computers allow the unique advantages of different types of quantum systems to be exploited together in a single platform,” said lead author Ting Rei Tan. “Many research groups are pursuing this general approach. Each ion species is unique, and certain ones are better suited for certain tasks such as memory storage, while others are more suited to provide interconnects for data transfer between remote systems.”

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Supercharged LHC finds hints of entirely new particle

Two separate teams of physicists working with the Large Hadron Collider in Switzerland have identified signs of a new fundamental particle of nature. While hypotheses abound as to what exactly this particle could be — if it exists at all — the most popular opinion seems to be that it’s a heavier version of the Higgs boson, the particle that explains why other particles have mass.

“I don’t think there is anyone around who thinks this is conclusive,” one of the researchers, Kyle Cranmer from New York University, told The New York Times. “But it would be huge if true.”

After a hiatus of more than two years, the LHC was fired up again in June to continue smashing particles together — this time at record-breaking energy levels of around 13 trillion electron volts. (In case you’re wondering, an electron volt is a unit of energy equal to approximately 1.602×10-19 joules, and 6.5 trillion electron volts is twice the energy level used to detect the Higgs boson for the first time in 2012.)

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World’s most sensitive dark matter detector gets better

LEAD, S.D. [Brown University] — The Large Underground Xenon (LUX) dark matter experiment, which operates nearly a mile underground at the Sanford Underground Research Facility (Sanford Lab) in the Black Hills of South Dakota, has already proven itself to be the most sensitive dark matter detector in the world. Now, a new set of calibration techniques employed by LUX scientists has again dramatically improved its sensitivity.

Researchers with LUX are looking for WIMPs, weakly interacting massive particles, which are among the leading candidates for dark matter. “It is vital that we continue to push the capabilities of our detector in the search for the elusive dark matter particles,” said Rick Gaitskell, professor of physics at Brown University and co-spokesperson for the LUX experiment. “We have improved the sensitivity of LUX by more than a factor of 20 for low-mass dark matter particles, significantly enhancing our ability to look for WIMPs.”

The new research is described in a paper submitted to Physical Review Letters and posted to ArXiv. The work re-examines data collected during LUX’s first three-month run in 2013, and helps to rule out the possibility of dark matter detections at low-mass ranges where other experiments had previously reported potential detections.

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Scientists Create Most Expensive Material on Earth, Costs $4.2 Billion per Ounce

$4.2 billion per ounce. That’s how much the most expensive material on Earth costs. Priced at £100m per gram, the most expensive material on Earth is made up of “endohedral fullerenes,” a cage of carbon atoms containing nitrogen atoms. It could help us make atomic clocks and accurate autonomous cars.

Current atomic clocks are the size of rooms. This material could allow us to make atomic clocks that fit in your smartphone.

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