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Over the last decade, improvements in optical atomic clocks have repeatedly led to devices that have broken records for their precision (see Viewpoint: A Boost in Precision for Optical Atomic Clocks). To achieve even better performance, physicists must find a way to cool the atoms in these clocks to lower temperatures, which would allow them to use shallower atom traps and reduce measurement uncertainty. Tackling this challenge, Xiaogang Zhang and colleagues at the National Institute of Standards and Technology, Colorado, have cooled a gas of ytterbium atoms to a record low temperature of a few tens of nanokelvin [1]. As well as enabling the next generation of optical atomic clocks, the researchers say that their technique could be used to cool atoms in neutral-atom quantum computers.

Divalent atoms such as ytterbium are especially suited to precision metrology, as their lack of net electronic spin makes them less sensitive than other species to environmental noise. These atoms can be cooled to the necessary sub-µK temperatures in several ways, but not all techniques are compatible with the requirements of high-precision clocks. For example, evaporative cooling, in which the most energetic atoms are removed, is time-consuming and depletes the atoms. Meanwhile, resolved sideband cooling chills the motion of the atoms only along the axis of the 1D optical trap, leaving their off-axis motion unaffected.

Zhang and colleagues cool their atoms using a laser tuned to ytterbium’s so-called clock transition, whose extremely narrow linewidth means that the atom can theoretically be cooled to below 10 nK. They demonstrate that the precision of a clock employing a shallow lattice trap enabled by such a temperature would not be limited by atoms tunneling between adjacent lattice sites, potentially allowing a measurement uncertainty below 10^-19.

By leveraging a bizarre property of quantum mechanics called entanglement, quantum batteries could theoretically recharge in a flash. Now, progress is being made towards making them a reality.

For all of history, there’s been an underlying but unspoken assumption about the laws that govern the Universe: If you know enough information about a system, you can predict precisely how that system will behave in the future. The assumption is, in other words, deterministic. The classical equations of motion — Newton’s laws — are completely deterministic. The laws of gravity, both Newton’s and Einstein’s, are deterministic. Even Maxwell’s equations, governing electricity and magnetism, are 100% deterministic as well.

But that picture of the Universe got turned on its head with a series of discoveries that began in the late 1800s. Starting with radioactivity and radioactive decay, humanity slowly uncovered the quantum nature of reality, casting doubt on the idea that we live in a deterministic Universe. Predictively, many aspects of reality could only be discussed in a statistical fashion: where a set of probable outcomes could be presented, but which one would occur, and when, could not be precisely established. The hopes of avoiding the necessity of “quantum spookiness” was championed by many, including Einstein, with the most compelling alternative to determinism put forth by Louis de Broglie and David Bohm. Decades later, Bohmian mechanics was finally put to an experimental test, where it failed spectacularly. Here’s how the best alternative to the spooky nature of reality simply didn’t hold up.

Going to smaller and smaller distance scales reveals more fundamental views of nature, which means if we can understand and describe the smallest scales, we can build our way to […].

The Quantum Insider (TQI) is the leading online resource dedicated exclusively to Quantum Computing.

“So a quantum key distribution consists of two things: No. 1, got to have a quantum random number generator, and that’s one of the things that QNu Labs makes,” he said. “The second thing that you need is the receivers in which those two devices connect and be used to convey encrypted messages in this fashion.”

In military use, quantum key distribution would work best in point to point communication — that is, communicating from one person to another. Creating a “true network” that’s able to send the same encrypted message to multiple receivers at once is challenging because the encrypted bit that’s carrying the message eventually begins to lose its coherence and “drops away,” Herman said.

“In the military, where you’re sending extremely sensitive classified data from one office to the next, you want to make sure that no one’s going to be able to break into and decrypt that,” he said. “Well, [quantum key distribution] is definitely a way in which to carry that out.”

Quantum Physics is the bedrock of physical reality, as far as we know, but things behave very differently at the quantum level than they do in the world as we know it. Today, we learn how large number probability turns a probabilistic world into a deterministic one.

This video is episode two from the series “Examining the Big Questions of Time”.
Stream the full series now on Wondrium http://www.Wondrium.com/YouTube.

Just a few decades ago, scientists were absolute in their determination that time began with the Big Bang. But that’s all been turned on its head with the rise of string theory and other fascinating developments in theoretical physics. Learn how those advances brought the pre-Bang universe to the forefront of cosmology.

Continue reading “The Myth of The Beginning of Time | String Theory and the Big Bang” »

The popularity of electric vehicles (EVs) as an environmentally friendly alternative to conventional gasoline vehicles has been on the rise. This has led to research efforts directed toward developing high-efficiency EV batteries. But, a major inefficiency in EVs results from inaccurate estimations of the battery charge. The charge state of an EV battery is measured based on the current output of the battery. This provides an estimate of the remaining driving range of the vehicles.

Typically, the battery currents in EVs can reach hundreds of amperes. However, commercial sensors that can detect such currents cannot measure small changes in the current at milliampere levels. This leads to an ambiguity of around 10% in the battery charge estimation. What this means is that the driving range of EVs could be extended by 10%. This, in turn, would reduce inefficient battery usage.

Now, a team of researchers from Japan, led by Professor Mutsuko Hatano from Tokyo Institute of Technology (Tokyo Tech), has now come up with a solution. In their study published in Scientific Reports, the team has reported a diamond quantum sensor-based detection technique that can estimate the battery charge within 1% accuracy while measuring high currents typical of EVs.