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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. Thatâs 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). Letâs learn how to cheat the universe.
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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 âsqueezingâ â including a fourth-order effect known as quadsqueezing â 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, âIt 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 donât believe me, ask her.â
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.
#QuantumMechanics #SimulationHypothesis.
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 â 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 isnât 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 weâve 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.
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ABOUT WORLD SCIENCE FESTIVAL:
âThe 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,â said Dr. Oana BÄzÄvan, lead author from the Department of Physics, University of Oxford.
âThe 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,â BÄzÄvan added.
Physicists have long used a trick called âsqueezingâ 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.
Is there a quantum reason we could have free will? Neil deGrasse Tyson and comedian Chuck Nice explore the concept of free will and predetermination with neuroscientist, biologist, and author of Determined: The Science of Life Without Free Will, Robert Sapolsky.
A special thanks from our editors to Robert Sapolskyâs dog.
Could we put an end to the question of whether or not we have free will? Discover âThe Hungry Judge Effectâ and how little bits of biology affect our actions. We break down a physicistâs perspective of free will, The Big Bang, and chaos theory. Is it enough to just feel like we have free will? Why is it an issue to think you have free will if you donât?
We discuss the difference between free will in big decisions versus everyday decisions. How do you turn out to be the type of person who chooses vanilla ice cream over strawberry? We explore how quantum physics and virtual particles factor into predetermination. Could quantum randomness change the actions of an atom? How can society best account for a lack of free will? Are people still responsible for their actions?
What would Chuck do if he could do anything he wanted? We also discuss the benefits of a society that acknowledges powers outside of our control and scientific advancements made. How is meritocracy impacted by free will? Plus, can you change if people believe in free will if they have no free will in believing so?
Thanks to our Patrons Pro Handyman, Brad K. Daniels, Starman, Stephen Somers, Nina Kane, Paul Applegate, and David Goldberg for supporting us this week.
XPP, the X-ray Pump Probe instrument at the Linac Coherent Light Source (LCLS), is back online and welcoming researchers after a complete rebuild. The overhaul has readied XPP for the significant increase in X-ray output expected from the ongoing high-energy upgrade to LCLS at the Department of Energyâs SLAC National Accelerator Laboratory. LCLS is a pioneering X-ray free-electron laser facility used by scientists around the world to capture ultrafast snapshots of natural processes.
âCompleting the XPP rebuild on-time and on-budget is a key milestone for the high-energy upgrade effort, and weâre thrilled that the instrument is back to supporting researchers from around the world,â said John Hogan, project director for the LCLS high-energy upgrade. âThis was a huge team effort, involving partners across SLACâs engineering, science and project teams.â
Since its 2010 debut, XPP has enabled groundbreaking research across materials scienceâfrom quantum information storage to material dynamics across timescalesâas well as studies in chemistry, physics and bioscience. Researchers have leveraged XPP to pioneer X-ray optics technologies, including cavity-based X-ray oscillators that are shaping future X-ray free-electron laser facilities.
In thermodynamics, an âadiabatic processâ is a system change that transfers no heat in or out of the system. Any and all energy change in that system are therefore accomplished by doing work on the system, work being action that moves matter over a distance. (An example is a bicycle tire pump or lifting a box from the floor.)
The âadiabatic theoremâ says that if you change a system slowly enough, it will remain in the same energy state. For example, if you walk slowly enough holding a full cup of coffee, the coffee will not spillâthe coffee system has time to relax back to its steady stateâbut if you make a quick and sudden change while holding the coffee cup, some coffee will spill over the cupâs edge.
There is a similar theorem in quantum mechanicsâa quantum system that is changed (perturbed) slowly enough will remain in its existing quantum state (often its ground state), while a sudden change, such as a photon impinging upon an atom, changes its energy state.