Lifeboat Foundation

And that’s where physicists are getting stuck.

Zooming in to that hidden center involves virtual particles — quantum fluctuations that subtly influence each interaction’s outcome. The fleeting existence of the quark pair above, like many virtual events, is represented by a Feynman diagram with a closed “loop.” Loops confound physicists — they’re black boxes that introduce additional layers of infinite scenarios. To tally the possibilities implied by a loop, theorists must turn to a summing operation known as an integral. These integrals take on monstrous proportions in multi-loop Feynman diagrams, which come into play as researchers march down the line and fold in more complicated virtual interactions.

Physicists have algorithms to compute the probabilities of no-loop and one-loop scenarios, but many two-loop collisions bring computers to their knees. This imposes a ceiling on predictive precision — and on how well physicists can understand what quantum theory says.

Over the past several decades, researchers have moved from using electric currents to manipulating light waves in the near-infrared range for telecommunications applications such as high-speed 5G networks, biosensors on a chip, and driverless cars. This research area, known as integrated photonics, is fast evolving and investigators are now exploring the shorter—visible—wavelength range to develop a broad variety of emerging applications. These include chip-scale LIDAR (light detection and ranging), AR/VR/MR (augmented/virtual/mixed reality) goggles, holographic displays, quantum information processing chips, and implantable optogenetic probes in the brain.

The one device critical to all these applications in the visible range is an optical phase modulator, which controls the phase of a light wave, similar to how the phase of radio waves is modulated in wireless computer networks. With a phase modulator, researchers can build an on-chip optical switch that channels light into different waveguide ports. With a large network of these optical switches, researchers could create sophisticated integrated optical systems that could control light propagating on a tiny chip or light emission from the chip.

But phase modulators in the visible range are very hard to make: there are no materials that are transparent enough in the visible spectrum while also providing large tunability, either through thermo-optical or electro-optical effects. Currently, the two most suitable materials are silicon nitride and lithium niobate. While both are highly transparent in the visible range, neither one provides very much tunability. Visible-spectrum phase modulators based on these materials are thus not only large but also power-hungry: the length of individual waveguide-based modulators ranges from hundreds of microns to several mm and a single modulator consumes tens of mW for phase tuning. Researchers trying to achieve large-scale integration—embedding thousands of devices on a single microchip—have, up to now, been stymied by these bulky, energy-consuming devices.

The most promising application in biomedicine is in computational chemistry, where researchers have long exploited a quantum approach. But the Fraunhofer Society hopes to spark interest among a wider community of life scientists, such as cancer researchers, whose research questions are not intrinsically quantum in nature.

“It’s uncharted territory,” says oncologist Niels Halama of the DKFZ, Germany’s national cancer center in Heidelberg. Working with a team of physicists and computer scientists, Halama is planning to develop and test algorithms that might help stratify cancer patients, and select small subgroups for specific therapies from heterogeneous data sets.

This is important for precision medicine, he says, but classic computing has insufficient power to find very small groups in the large and complex data sets that oncology, for example, generates. The time needed to complete such a task may stretch out over many weeks—too long to be of use in a clinical setting, and also too expensive. Moreover, the steady improvements in the performance of classic computers are slowing, thanks in large part to fundamental limits on chip miniaturization.

Check out the physics courses that I mentioned (many of which are free!) and support this channel by going to https://brilliant.org/Sabine/ where you can create your Brilliant account. The first 200 will get 20% off the annual premium subscription.

What are the quantum technologies that are now attracting so much research funding? In this video I go through the most important ones: quantum computing, quantum metrology, the quantum internet, and quantum simulations. I explain what these are all about and how likely they are to impact our lives soon. I also tell you what frequently headline blunders to watch out for.

Continue reading “Don’t fall for quantum hype” »

Work has potential applications in quantum computing, and introduces new way to plumb the secrets of superconductivity. MIT physicists and colleagues have demonstrated an exotic form of superconductivity in a new material the team synthesized only about a year ago. Although predicted in the 1960s.

“An important theme of our research is that new physics comes from new materials,” says Joseph Checkelsky, lead principal investigator of the work and the Mitsui Career Development Associate Professor of Physics. “Our initial report last year was of this new material. This new work reports the new physics.”

Checkelsky’s co-authors on the current paper include lead author Aravind Devarakonda PhD ’21, who is now at Columbia University. The work was a central part of Devarakonda’s thesis. Co-authors are Takehito Suzuki, a former research scientist at MIT now at Toho University in Japan; Shiang Fang, a postdoc in the MIT Department of Physics; Junbo Zhu, an MIT graduate student in physics; David Graf of the National High Magnetic Field Laboratory; Markus Kriener of the RIKEN Center for Emergent Matter Science in Japan; Liang Fu, an MIT associate professor of physics; and Efthimios Kaxiras of Harvard University.

Continue reading “Exotic New Material Could Be Two Superconductors in One — With Serious Quantum Computing Applications” »

Superconductivity occurs when electrons in a metal pair up and move through the material without resistance. But there may be more to the story than we thought, as scientists in Germany have now discovered that electrons can also group together into families of four, creating a new state of matter and, potentially, a new type of superconductivity.

Conductivity is a measure of how easily electrons (and therefore electricity) can move through a material. But even in materials that make good conductors, like gold, electrons will still encounter some resistance. Superconductors, however, remove all such barriers and provide zero resistance at ultracold temperatures.

The reason electrons can move through superconductors so easily is because they pair up through a quantum effect known as Cooper pairing. In doing so, they raise the minimum amount of energy it takes to interfere with the electrons – and if the material is cold enough, its atoms won’t have enough thermal energy to disturb these Cooper pairs, allowing the electrons to flow freely with no loss of energy.

What is entanglement theory? It is a Mystery, and here is a potential solution. But its implications are so paradigm shattering that most scientists refuse to believe it. Maybe we can’t handle the truth?

Imagine you found a pair of dice such that no matter how you tossed them, they always added up to 7. Besides becoming the richest man in Vegas, what you would have there is something called an entangled pair of dice.

Continue reading “Entanglement Theory may Reveal a Reality we can’t Handle” »

In this video I explain why free will is incompatible with the currently known laws of nature and why the idea makes no sense anyway. However, you don’t need free will to act responsibly and to live a happy life, and I will tell you why.

Support me on Patreon: https://www.patreon.com/Sabine.

Continue reading “You don’t have free will, but don’t worry” »

But IBM’s latest quantum chip and its competitors face a long path towards making the machines useful.