Simulations of ‘backwards time travel’ can improve scientific experiments

Image Credit: Scientific Frontline stock graphic

If gamblers, investors and quantum experimentalists could bend the arrow of time, their advantage would be significantly higher, leading to significantly better outcomes. 

Researchers at the University of Cambridge have shown that by manipulating entanglement – a feature of quantum theory that causes particles to be intrinsically linked – they can simulate what could happen if one could travel backwards in time. So that gamblers, investors and quantum experimentalists could, in some cases, retroactively change their past actions and improve their outcomes in the present.

Whether particles can travel backwards in time is a controversial topic among physicists, even though scientists have previously simulated models of how such spacetime loops could behave if they did exist. By connecting their new theory to quantum metrology, which uses quantum theory to make highly sensitive measurements, the Cambridge team has shown that entanglement can solve problems that otherwise seem impossible. The study appears in the journal Physical Review Letters.

“Imagine that you want to send a gift to someone: you need to send it on day one to make sure it arrives on day three,” said lead author David Arvidsson-Shukur, from the Hitachi Cambridge Laboratory. “However, you only receive that person’s wish list on day two. So, in this chronology-respecting scenario, it’s impossible for you to know in advance what they will want as a gift and to make sure you send the right one.

An electrical switch to control chemical reactions

The device takes the form of a small box in which the reaction medium circulates between two electrodes producing the electric field.
Photo Credit: © Stefan Matile

New pharmaceuticals, cleaner fuels, biodegradable plastics: in order to meet society’s needs, chemists have to develop new synthesis methods to obtain new products that do not exist in their natural state. A research group at the University of Geneva (UNIGE), in collaboration with Cardiff University, has discovered how to use an external electric field to control and accelerate a chemical reaction, like a "switch". This work, to be read in Science Advances, could have a considerable impact on the development of new molecules, enabling not only more environmentally friendly synthesis, but also very simple external control of a chemical reaction.

In chemistry, creating complex organic chemical compounds from simpler reagents is denoted "organic synthesis". Through successive reactions, chemists assemble small molecules to ultimately form the desired products. Organic synthesis is crucial to the manufacture of drugs, polymers, agrochemicals, pigments and fragrances. These successive steps are extremely precise and delicate to control. To limit the required resources, the yield of each reaction step should be optimal. Achieving better control and simpler operation of these reactions remains a major research challenge.

New study reveals the influence of natural climate drivers on extreme monsoons in Pakistan

Satellite image of flooding in Pakistan in August 2022.
Image Credit: Moetasim Ashfaq

A new study by researchers at the Department of Energy’s Oak Ridge National Laboratory looks at some of the influences that could be driving the increasingly severe weather over Pakistan.

Published in npj Climate and Atmospheric Science, the study analyzed over 40 years of data and found that natural climate variability, which includes factors such as sea surface temperature and jet stream anomalies, accounts for over 70% of observed monsoon variability and extremes in Pakistan during the 21st century — with climate change potentially adding to their severity.

Pakistan is no stranger to floods and droughts. However, these events have become more frequent and severe in recent decades — unprecedented rainfall in 2010 and 2022 caused catastrophic floods and landslides, and a drought at the beginning of the 21st century caused widespread famine.

Climate scientists must quantify the influence of natural climate variability on these extreme weather events to understand how and the extent to which climate change has contributed to this increased volatility.

The study, called “The influence of natural variability on extreme monsoons in Pakistan,” focused on precipitation variability in West South Asia, a region that includes Pakistan and parts of India. The South Asian climate is commonly studied due to the area’s high population and strong monsoon season, which can bring up to 70% of the annual rainfall in a few months. 

Drug-filled nanocapsule helps make immunotherapy more effective in mice

Image illustrates the effect of lactate oxidase (LOx) nanocapsules (depicted in orange) within solid tumors. By reducing lactate concentrations and generating hydrogen peroxide in the tumor microenvironment, these nanocapsules promote the infiltration and activation of T cells (depicted in blue and green).
Image Credit: Courtesy of the Jing Wen laboratory.

UCLA researchers have developed a new treatment method using a tiny nanocapsule to help boost the immune response, making it easier for the immune system to fight and kill solid tumors.

The investigators found the approach, described in the journal Science Translational Medicine, increased the number and activity of immune cells that attack the cancer, making cancer immunotherapies work better.

“Cancer immunotherapy has reshaped the landscape of cancer treatment,” said senior author of the study Jing Wen, assistant adjunct professor of microbiology, immunology, & molecular genetics at the David Geffen School of Medicine at UCLA and a scientist at the UCLA Jonsson Comprehensive Cancer Center. “However, not all patients with solid tumors respond well to immunotherapy, and the reason seems to be related to the way the cancer cells affect their surroundings.”

Cancer cells produce a lot of lactate, Wen explained, which creates an environment around the solid tumor that makes it difficult for the immune system to work effectively against the cancer.

Cannabis intoxication triggers cognitive mechanism of addiction

Photo Credit: Matthew Brodeur

New research from the Institute of Psychiatry, Psychology & Neuroscience (IoPPN) at King’s College London and the University of Oxford has found that the main component of cannabis, delta-9-tetrahydrocannabinol (THC), leads to people’s attention being more drawn to other cannabis stimuli when using the drug, which researchers suggest could underpin the cognitive mechanisms behind cannabis use disorder (CUD).

The research, published in Addiction, also found that levels of cannabidiol (CBD) typically found in cannabis had no modulating effects on the participants, despite many users believing this to be the case.

Over the course of four sessions, researchers asked 46 infrequent cannabis users (using cannabis less than once a week) to inhale a cannabis vapour containing 10mg of THC, and either 0, 10, 20, or 30mg of CBD. They were then given a task designed to measure what they focused on more when given the choice between options of images (cannabis stimuli vs neutral and food stimuli vs neutral).

Researchers found that the acute inhalation of THC resulted in people being more drawn to cannabis-related cues without explicitly liking it more.

Cleaner Snow Boosts Future Snowpack Predictions

Photo Credit: Nick Kwan

Less pollution settling into snow should help cut the decline of snowpack in the Northern Hemisphere later this century. Though the snowpack will still diminish due to rising temperatures, the outlook is less dire when the cleaner snow of the future is considered.

In some scenarios, the researchers predict that the reduction in snowpack will be less than half what has been predicted—good news for the many people who rely on subsequent snowmelt in high mountains for water and food production, as well as for those who depend on winter recreation.

The findings come from scientists at the Department of Energy’s Pacific Northwest National Laboratory who weighed several factors that affect snowpack. These include warming temperatures, pollution, dust and even the shape of snow grains as they pack together on the ground.

Close con­nectiv­ity within the North At­lantic Cur­rent sys­tem iden­ti­fied

An acous­tic cur­rent meter, built into a moor­ing buoy be­ing pre­pared for de­ploy­ment in the At­lantic. The ocean cur­rent is meas­ured with these in­stru­ments.
Photo Credit: MARUM – Cen­ter for Mar­ine En­vir­on­mental Sci­ences, Uni­versity of Bre­men, D. Kieke

Long-term com­par­at­ive study re­veals par­al­lels between time series from Flor­ida and New­found­land

Re­search­ers from the Uni­versity of Bre­men and the Fed­eral Mari­time and Hy­dro­graphic Agency have com­pared long-term data on the At­lantic Me­ri­di­onal Over­turn­ing Cir­cu­la­tion from two dif­fer­ent lat­it­udes and dis­covered a stat­ist­ical cor­rel­a­tion. Their aim was to in­vest­ig­ate how the At­lantic Me­ri­di­onal Over­turn­ing Cir­cu­la­tion has de­veloped over a period of 25 years, based on moored ob­ser­va­tion sta­tions. These data will help to re­fine cli­mate mod­els in the fu­ture. The study has been pub­lished in the journal Geophysical Research Letters.

In ad­di­tion to wind, tem­per­at­ure and sa­lin­ity are the driv­ing forces of ocean cur­rents in the North At­lantic. They trans­port warm, salty wa­ter from the sub­trop­ical re­gions north­ward to the colder, lower-sa­lin­ity areas. Like the wind-driven Gulf Stream, these cur­rents are com­pon­ents of the At­lantic Me­ri­di­onal Over­turn­ing Cir­cu­la­tion (AMOC). Be­cause of the im­mense amount of heat it trans­ports, the AMOC is an im­port­ant part of the global cli­mate sys­tem. For ex­ample, it in­flu­ences re­gional pre­cip­it­a­tion as well as strong trop­ical storms, and acts as a re­mote heat­ing sys­tem for Europe’s cli­mate.

A new lens” into the Universe’s most energetic particles

An example of a cosmic-ray extensive air shower recorded by the Subaru Telescope. The highlighted tracks, which are mostly aligned in similar directions, show the shower particles induced from a high-energy cosmic ray. 
Image Credit: National Astronomical Observatory of Japan, Hyper Suprime-Cam (HSC) Collaboration

Showers in bathrooms bring us comfort; showers from space bring astrophysicists joy. Osaka Metropolitan University scientists have observed, with their novel method, cosmic-ray extensive air showers with unprecedented precision, opening the door to new insights into the Universe’s most energetic particles.

When a high energy cosmic ray collides with the Earth's atmosphere, it generates an enormous number of particles known as an extensive air shower. A research team led by Associate Professor Toshihiro Fujii from the Graduate School of Science and Nambu Yoichiro Institute of Theoretical and Experimental Physics at Osaka Metropolitan University, along with graduate student Fraser Bradfield, has discovered that the prime-focus wide field camera mounted on the Subaru Telescope, situated atop the Mauna Kea volcano in Hawaii, can capture these extensive air showers with extremely high resolution.

“Starquakes” could explain mystery signals

Earthquake map. Data on earthquakes was taken from Japan’s Kanto region (including Tokyo and Narita) and Izumo in the Chugoku region (north of Hiroshima). Black dots represent the epicenters of earthquakes recorded between May 6, 2010, and December 31, 2012.
Image Credit: ©2023 T. Totani & Y. Tsuzuki

Fast radio bursts, or FRBs, are an astronomical mystery, with their exact cause and origins still unconfirmed. These intense bursts of radio energy are invisible to the human eye, but show up brightly on radio telescopes. Previous studies have noted broad similarities between the energy distribution of repeat FRBs, and that of earthquakes and solar flares. However, new research at the University of Tokyo has looked at the time and energy of FRBs and found distinct differences between FRBs and solar flares, but several notable similarities between FRBs and earthquakes. This supports the theory that FRBs are caused by “starquakes” on the surface of neutron stars. This discovery could help us better understand earthquakes, the behavior of high-density matter and aspects of nuclear physics.

The vastness of space holds many mysteries. While some people dream of boldly going where no one has gone before, there is a lot we can learn from the comfort of Earth. Thanks to technological advances, we can explore the surface of Mars, marvel at Saturn’s rings and pick up mysterious signals from deep space. Fast radio bursts are hugely powerful, bright bursts of energy which are visible on radio waves. First discovered in 2007, these bursts can travel billions of light years but typically last mere thousandths of a second. It has been estimated that as many as 10,000 FRBs may happen every day if we could observe the whole sky. While the sources of most bursts detected so far appear to emit a one-off event, there are about 50 FRB sources which emit bursts repeatedly.

Researchers capture first-ever afterglow of huge planetary collision in outer space

Image shows a visualization of the huge, glowing planetary body produced by a planetary collision. In the foreground, fragments of ice and rock fly away from the collision and will later cross in between Earth and the host star which is seen in the background of the image.
Illustration Credit: Mark Garlick

A chance social media post by an eagle-eyed amateur astronomer sparked the discovery of an explosive collision between two giant planets, which crashed into each other in a distant space system 1,800 light years away from planet Earth.

The study, published today in Nature, reports the sighting of two ice giant exoplanets colliding around a sun-like star, creating a blaze of light and plumes of dust. Its findings show the bright heat afterglow and resulting dust cloud, which moved in front of the parent star dimming it over time.

The international team of astronomers was formed after an enthusiast viewed the light curve of the star and noticed something strange. It showed the system doubled in brightness at infrared wavelengths some three years before the star started to fade in visible light.

Co-lead author Dr Matthew Kenworthy, from Leiden University, said: “To be honest, this observation was a complete surprise to me. When we originally shared the visible light curve of this star with other astronomers, we started watching it with a network of other telescopes.