Quantum physics

Postdoctoral research Wenxuan Jia PhD '24 and colleagues at the Laser Interferometer Gravitational-Wave Observatory (LIGO) have developed a way to reduce the impact of quantum noise by squeezing the laser light used in the detectors, enabling scientists to double the number of gravitational waves they can find, reports Karmela Padavic-Callaghan for New Scientist. “We realized that quantum noise will be limiting us a long time ago,” says Jia. “It’s not just a fancy [quantum] thing to demonstrate, it’s something that really affects the actual detector.” 

Postdoctoral associate Adam Forrest Kay’s book “Escape From Shadow Physics: The Quest to End the Dark Ages of Quantum Theory,” is reviewed by Andrew Crumey for The Wall Street Journal. “Consistently interesting” and “energetically written,” the book, “eloquently explains the history behind hydrodynamic quantum analogs,” writes Crumey.  

Prof. Seth Lloyd and other physicists have begun to show that in the quantum realm, theoretical routes to the past called time loops might be closer to reality, writes New Scientist’s Miriam Frankel. When first publishing his ideas about quantum time loops, Lloyd says he “probably wouldn’t have done it” given all the questions received about time travel, but now testing time loops is experimentally feasible.

Science reporter Jennifer Sills asked scientists to answer the question: “Imagine that you meet all of your research goals. Describe the impact of your research from the perspective of a person, animal, plant, place, object, or entity that has benefited from your success.” Xiangkun (Elvis) Cao, a Schmidt Science Fellow in the MIT Department of Chemical Engineering, shares his response from a photon’s perspective. “I am a photon,” writes Cao. “I started my journey entangled with my significant other at the beginning of the Universe. In the past, humans couldn’t understand me, but then physicists created a quantum computer. At last, I have been reunited with my life partner!”

MIT scientists have found that the “motions of undulating animals and the states of quantum objects can be described using strikingly similar equations,” writes Karmela Padavic-Callaghan for New Scientist. The similarity “allowed the team to use mathematical tools previously developed by quantum physicists to analyze the animals,” notes Padavic-Callaghan. “For instance, the team quantified how differently a snake-like robot and a C. elegans move and created a diagram that placed them on a spectrum of other undulating creatures.”

MIT scientists have developed a new way of colliding ultracold molecules while controlling the rate at which they react, reports Martijn Boerkamp for Physics World. “Our work is a step to achieve quantum control over molecular collisions and reactions and to map out more broadly the collisional properties of these molecules with the goal of finding a deeper understanding,” explains Prof. Wolfgang Ketterle.

Gizmodo reporter Isaac Schultz writes that researchers from MIT, Caltech and elsewhere have found that “quantum systems can imitate wormholes, theorized shortcuts in spacetime, in that the systems allow the instantaneous transit of information between remote locations.” Grad student Alexander Zlokapa explains that: “We performed a kind of quantum teleportation equivalent to a traversable wormhole in the gravity picture. To do this, we had to simplify the quantum system to the smallest example that preserves gravitational characteristics so we could implement it.”

Physicists from MIT and elsewhere have created a small “wormhole” effect between two quantum systems on the same processor and were able to send a signal through it, reports Charlotte Hu for Popular Science. This new model is a “way to study the fundamental problems of the universe in a laboratory setting,” writes Hu. 

Researchers at MIT and elsewhere have created a holographic wormhole using Google’s Sycamore quantum computer, reports Sarah Wells for Vice. “The researchers created an entangled state (a quantum mechanical phenomena where distant particles can still communicate with each other) between two halves of a quantum computer and sent a message in between,” writes Wells. “This message was scrambled as it entered the system and, through entanglement, unscrambled on the other side.”

A team of researchers, including scientists from MIT, “simulated a pair of black holes in a quantum computer and sent a message between them through a shortcut in space-time called a wormhole,” reports Dennis Overbye for The New York Times. The development is another “step in the effort to understand the relation between gravity, which shapes the universe, and quantum mechanics, which governs the subatomic realm of particles,” writes Overbye.

Prof. David Kaiser discussed the significance of Alain Aspect, John F. Clauser and Anton Zeilinger’s research conducting experiments concerning quantum entanglement, for which they were honored with the 2022 Nobel Prize in Physics. “Clauser got a lot of pushback from scientists who didn’t think this was even part of science,” said Kaiser. “He had to have a lot of stick-to-itiveness to publish his result.”

Popular Science reporter Rahul Rao writes that researchers from MIT and Harvard have whipped up quantum tornadoes, “the latest demonstration of quantum mechanics—the strange code of laws that governs the universe at its finest, subatomic scales.”

Researchers from MIT and Harvard have directly observed a quantum tornado, reports Elizabeth Gamillo for Smithsonian. “Scientists observed the tornado-like behavior after trapping and spinning a cloud of one million sodium atoms using lasers and electromagnets at 100 rotations per second,” writes Gamillo.

UPI reporter Brooks Hays writes that LIGO researchers have cooled a human-scale object to a near standstill. "One of the questions that we might be able to answer is: 'Why do large objects not naturally appear in quantum states?' There are various conjectures for why that might be; some say that gravity -- which acts strongly on larger objects -- might be responsible," explains Prof. Vivishek Sudhir. "We now have a system where some of these conjectures can be experimentally tested.”

LIGO researchers have nearly frozen the motion of atoms across four mirrors used to detect ripples in space-time, reports Isaac Schultz for Gizmodo. “We could actually use the same capability of LIGO to do this other thing, which is to use LIGO to measure the random jiggling motion of these mirrors—use that information which we have about the motion—and apply a counteracting force, so that you know you would stop the atoms from moving,” says Prof. Vivishek Sudhir.