Scientists have created a powerful new way to control quantum systems, achieving the first-ever demonstration of quadsqueezing—an elusive fourth-order quantum effect. By combining simple forces in a clever way, they made previously hidden quantum behaviors visible and usable, opening new frontiers for quantum technology.
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In his essay “The Unreasonable Effectiveness of Mathematics”, the physicist Eugine Wigner said that “the enormous usefulness of mathematics in the natural sciences is something bordering on the mysterious”. This statement was inspired by the observation that so many aspects of the physical world seem to be describable and predictable by mathematical equations to incredible precision especially as quantum phenomena. But quantum phenomena have no subjective qualities and have questionable physicality. They seem to be completely describable by only numbers, and their behavior precisely defined by equations. In a sense, the quantum world is made of math. So does that mean the universe is made of math too? If you believe the Mathematical Universe Hypothesis then yes. And so are you.
Does quantum mechanics allow the future to retroactively influence the past, as in the infamous delayed choice quantum eraser experiment? How about we get an actual quantum physicist–who many of you already know–to show us how to do this experiment at home, and hopefully set this matter to rest.
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If you used every particle in the observable universe to do a full quantum simulation, how big would that simulation be? At best a large molecule. That’s how insanely information dense the quantum wavefunction really is. And yet we routinely simulate systems with thousands, even millions of particles. How? By cheating. Using the ultimate compression algorithm: Density Functional Theory (DFT). Let’s learn how to cheat the universe.
Researchers at the University of Oxford have demonstrated a new type of quantum interaction using a single trapped ion. By creating and controlling increasingly complex forms of “squeezing” – including a fourth-order effect known as quadsqueezing – the team has, for the first time, made previously unreachable quantum effects experimentally accessible.
The approach also provides a new way to engineer these interactions, with potential applications in quantum simulation, sensing, and computing. Their results have been published in Nature Physics.
Many systems in physics behave like tiny objects that vibrate or swing back and forth, like a spring or a pendulum. In quantum physics, these are known as quantum harmonic oscillators. Light waves, vibrations in molecules, and even the motion of a single trapped atom can all be described in this way. Controlling these systems is important for quantum technologies, from ultra-precise sensors to new kinds of quantum computers.
As Homer tells us, Odysseus made an epic journey, against the odds, from Troy to his home in Ithaca. He visited many lands, but mostly dwelt with the nymph Calypso on her island. We can imagine that his wife, Penelope, would have asked him about that particular time. Odysseus might have replied, “It was nothing. In fact, it was less than nothing. Negative five years I dwelt with Calypso. How else could I have arrived home after only ten years? If you don’t believe me, ask her.”
Quantum particles, it turns out, are just as wily as Odysseus, as we have shown in an experiment published in Physical Review Letters. Not only can their arrival time suggest that they dwelt with other particles for a negative amount of time, but if one asks those other particles, they will corroborate the story.
Is reality actually real? In this mind-bending 29-minute exploration, theoretical physicist Richard Feynman takes you on a deep dive into quantum mechanics, the double-slit experiment, and the most unsettling discoveries in the history of science — discoveries that suggest the solid, physical world you experience every day may be far less \.
Does quantum mechanics actually imply that every possible outcome of every decision happens somewhere in an expansive reality? And if so, what does that mean for probability, free will, and our understanding of the universe itself?
Brian Greene sits down with David Deutsch, widely regarded as the father of quantum computing, to examine what many physicists are still reluctant to accept about their own theory. They explore why the many-worlds interpretation isn’t just a philosophical curiosity, what the wave function is really telling us about reality, and how decision theory may rescue probability in a fully deterministic multiverse. Deutsch also introduces constructor theory, his framework for rethinking the foundations of physics entirely and explains why the questions we’ve been trained not to ask might be the most important ones in all of science.
This program is part of the Rethinking Reality series, supported by the John Templeton Foundation.
Participant: David Deutsch. Moderator: Brian Greene.
“The result is more than the creation of a new quantum state. It is a demonstration of a new method for engineering interactions that were previously out of reach,” said Dr. Oana Băzăvan, lead author from the Department of Physics, University of Oxford.
“The fourth-order quadsqueezing interaction was generated more than 100 times faster than expected using conventional approaches. This makes effects that were previously out of reach accessible in practice,” Băzăvan added.
Physicists have long used a trick called “squeezing” to sharpen the fuzzy measurements of the subatomic world. It is why gravitational-wave detectors, like LIGO, can hear black holes colliding across the universe. But for all its utility, ordinary squeezing is a relatively simple, second-order effect.