PRESS-NEWS.org - Press Release Distribution
PRESS RELEASES DISTRIBUTION

Mapping the optimal route between two quantum states

Experiment measures millions of quantum trajectories to predict 'most likely' route

Mapping the optimal route between two quantum states
2014-08-01
(Press-News.org) As a quantum state collapses from a quantum superposition to a classical state or a different superposition, it will follow a path known as a quantum trajectory. For each start and end state there is an optimal or "most likely" path, but it is not as easy to predict the path or track it experimentally as a straight-line between two points would be in our everyday, classical world.

In a new paper featured on the July 30 cover of Nature, scientists from the Institute for Quantum Studies at Chapman University, the University of Rochester, University of California at Berkeley, and Washington University in St. Louis have shown that it is possible to track these quantum trajectories and compare them to a recently developed theory for predicting the most likely path a system will take between two states.

Andrew N. Jordan, professor of physics at the University of Rochester and member of Chapman's Institute for Quantum Studies, is one of the authors of the paper. His group had developed this new theory in an earlier paper. The results published this week show good agreement between theory and experiment.

For their experiment, the Berkeley and Washington University teams devised a superconducting qubit with exceptional coherence properties, permitting it to remain in a quantum superposition during the continuous monitoring. The experiment actually exploited the fact that any measurement will perturb a quantum system. This means that the optimal path will come about as a result of the continuous measurement and how the system is being driven from one quantum state to another.

Kater Murch, co-author and assistant professor at Washington University in St. Louis, explained that a key part of the experiment was being able to measure each of these trajectories while the system was changing, something that had not been possible until now. This was made possible by using a breakthrough called "weak measurements" introduced by Chapman University's Yakir Aharonov.

"Everybody knows that if your only tool is a hammer, then you tend to treat everything as if it were a nail" says Prof. Jeff Tollaksen, Director of Chapman's Institute for Quantum Studies. "But a whole new world opens up when we make weak measurements."

Jordan compares the experiment to watching butterflies make their way one by one from a cage to nearby trees.

"Each butterfly's path is like a single run of the experiment," said Jordan. "They are all starting from the same cage, the initial state, and ending in one of the trees, each being a different end state."

By watching the quantum equivalent of a million butterflies make the journey from cage to tree, the researchers were in effect able to predict the most likely path a butterfly took by observing which tree it landed on (known as post-selection in quantum physics measurements), despite the presence of a wind, or any disturbance that affects how it flies (which is similar to the effect measuring has on the system).

"The experiment demonstrates that for any choice of final quantum state, the most likely or 'optimal path' connecting them in a given time can be found and predicted," said Jordan. "This verifies the theory and opens the way for active quantum control techniques."

He explained that only if you know the most likely path is it possible to set up the system to be in the desired state at a specific time.

INFORMATION: Jordan and Tollaksen recently wrote about these results in a Springer book titled Quantum Theory: a Two-Time Success Story. Yakir Aharonov Festschrift (edited by Struppa and Tollaksen). Jordan also recently gave a talk at the Institute for Quantum Studies on the subject of the cover story for Nature. The talk can be viewed at http://ibc.chapman.edu/Mediasite/Play/2620fe48c1e243388d890ab0352f2fa41d.

Consistently ranked among the top universities in the West, Chapman University provides a uniquely personalized and interdisciplinary educational experience to highly qualified students. Our programs encourage innovation, creativity and collaboration, and focus on developing global citizen-leaders who are distinctively prepared to improve their community and their world. Visit http://www.chapman.edu Follow us on Facebook at: Chapman University Facebook On Twitter at: @ChapmanU On YouTube at: Chapman University YouTube Channel


[Attachments] See images for this press release:
Mapping the optimal route between two quantum states

ELSE PRESS RELEASES FROM THIS DATE:

Cordilleran terrane collage

Cordilleran terrane collage
2014-08-01
Boulder, Colo., USA - In the August 2014 issue of LITHOSPHERE, Steve Israel of the Yukon Geological Survey and colleagues provide conclusions regarding the North American Cordillera that they say "are provocative in that they blur the definition of tectonic terranes, showing that many observations of early geologists can be attributed to evolving geologic processes rather than disparate geologic histories." Western North America is characterized by the Cordilleran accretionary mountain belt, which has seen episodic plate convergence since the early Paleozoic, about 253 ...

On-chipt topological light

On-chipt topological light
2014-08-01
Topological transport of light is the photonic analog of topological electron flow in certain semiconductors. In the electron case, the current flows around the edge of the material but not through the bulk. It is "topological" in that even if electrons encounter impurities in the material the electrons will continue to flow without losing energy. In the photonic equivalent, light flows not through and around a regular material but in a meta-material consisting of an array of tiny glass loops fabricated on a silicon substrate. If the loops are engineered just right, ...

Society bloomed with gentler personalities and more feminine faces

Society bloomed with gentler personalities and more feminine faces
2014-08-01
DURHAM, N.C. -- Modern humans appear in the fossil record about 200,000 years ago, but it was only about 50,000 years ago that making art and advanced tools became widespread. A new study appearing Aug. 1 in the journal Current Anthropology finds that human skulls changed in ways that indicate a lowering of testosterone levels at around the same time that culture was blossoming. "The modern human behaviors of technological innovation, making art and rapid cultural exchange probably came at the same time that we developed a more cooperative temperament," said lead author ...

History of culture visualized through art history, physics, complexity

History of culture visualized through art history, physics, complexity
2014-08-01
Coral Gables, Fla. (July 31, 2014) -- Quantifying and transforming the history of culture into visual representation isn't easy. There are thousands of individual stories, across thousands of years, to consider, and some historical conditions are nearly impossible to measure. Addressing this challenge, Dr. Maximilian Schich, associate professor of arts and technology at The University of Texas at Dallas, brought together a team of network and complexity scientists, including University of Miami physicist Chaoming Song, to create and quantify a big picture of European ...

'Normal' bacteria vital for keeping intestinal lining intact

2014-08-01
August 1, 2014 — (BRONX, NY) — Scientists at Albert Einstein College of Medicine of Yeshiva University have found that bacteria that aid in digestion help keep the intestinal lining intact. The findings, reported online in the journal Immunity, could yield new therapies for inflammatory bowel disease (IBD) and a wide range of other disorders. The research involved the intestinal microbiome, which contains some 100 trillion bacteria. The role of these microorganisms in promoting or preventing disease is a major emerging field of study. Einstein scientists found that absorption ...

A train of 5 tropical cyclones in the Central and Eastern Pacific

A train of 5 tropical cyclones in the Central and Eastern Pacific
2014-08-01
A train of developing tropical low pressure areas stretch from the Eastern Pacific Ocean into the Central Pacific and they were captured in an image from NOAA's GOES-West satellite on August 1. The train of five tropical lows include the remnants of Tropical Storm Genevieve and newly developed Tropical Storm Iselle. NOAA's GOES-West satellite captured an image of the Pacific Ocean on August 1 at 1200 UTC (8 a.m. EDT) that showed post-tropical cyclone Genevieve's remnants between three other systems. The GOES-West image shows the train of storms with a well-developed Iselle ...

A map for eye disease

A map for eye disease
2014-08-01
Understanding eye diseases is tricky enough. Knowing what causes them at the molecular level is even more confounding. Now, University of Iowa researchers have created the most detailed map to date of a region of the human eye long associated with blinding diseases, such as age-related macular degeneration. The high-resolution molecular map catalogs thousands of proteins in the choroid, which supplies blood and oxygen to the outer retina, itself critical in vision. By seeing differences in the abundance of proteins in different areas of the choroid, the researchers can ...

NASA finds heavy rainfall and wind shear in newborn Tropical Storm Bertha

NASA finds heavy rainfall and wind shear in newborn Tropical Storm Bertha
2014-08-01
VIDEO: This 3-D flyby of Tropical Storm Bertha on Aug. 1 was created from TRMM satellite data. It shows (from the south) intense thunderstorms were reaching heights of over 15km (about... Click here for more information. The Tropical Rainfall Measuring Mission satellite known as TRMM found rain was falling heavily in the Atlantic Ocean's second tropical storm of the hurricane season. Bertha was close to the Lesser Antilles, prompting warnings and watches. The National Hurricane ...

Reptile Database surpasses 10,000 reptile species

Reptile Database surpasses 10,000 reptile species
2014-08-01
More than 10,000 reptile species have been recorded into the Reptile Database, a web-based catalogue of all living reptile species and classification, making the reptile species among the most diverse vertebrate groups in the world, alongside bird and fish species. For some time, experts have projected that 2014 would mark the year that reptiles would become the most diverse vertebrate group in the world. Reptiles include snakes, lizards, turtles, crocodiles, tuataras and amphisbaenians. "Officially, we have logged 10,038 reptile species into the database, which is ...

NASA sees Tropical Storm Halong's 'best side'

NASA sees Tropical Storm Halongs best side
2014-08-01
NASA satellite data showed Tropical Storm Halong's "best side" or most powerful side was east of its center. That's where the coldest cloud top temperatures and strongest thunderstorms appeared on satellite imagery. On August 1 at 13:30 UTC (9:30 a.m. EDT) the Moderate Resolution Imaging Spectroradiometer or MODIS instrument aboard NASA's Terra satellite captured an infrared picture of Tropical Storm Halong. The infrared data showed the coldest, strongest thunderstorm cloud-top temperatures east of the center of circulation. Cloud tops were as cold as -80F/-62C. Cloud ...

LAST 30 PRESS RELEASES:

Multi-resistance in bacteria predicted by AI model

Tinker Tots: A citizen science project to explore ethical dilemmas in embryo selection

Sensing sickness

Cost to build multifamily housing in California more than twice as high as in Texas

Program takes aim at drinking, unsafe sex, and sexual assault on college campuses

Inability to pay for healthcare reaches record high in U.S.

Science ‘storytelling’ urgently needed amid climate and biodiversity crisis

KAIST Develops Retinal Therapy to Restore Lost Vision​

Adipocyte-hepatocyte signaling mechanism uncovered in endoplasmic reticulum stress response

Mammals were adapting from life in the trees to living on the ground before dinosaur-killing asteroid

Low LDL cholesterol levels linked to reduced risk of dementia

Thickening of the eye’s retina associated with greater risk and severity of postoperative delirium in older patients

Almost one in ten people surveyed report having been harmed by the NHS in the last three years

Enhancing light control with complex frequency excitations

New research finds novel drug target for acute myeloid leukemia, bringing hope for cancer patients

New insight into factors associated with a common disease among dogs and humans

Illuminating single atoms for sustainable propylene production

New study finds Rocky Mountain snow contamination

Study examines lactation in critically ill patients

UVA Engineering Dean Jennifer West earns AIMBE’s 2025 Pierre Galletti Award

Doubling down on metasurfaces

New Cedars-Sinai study shows how specialized diet can improve gut disorders

Making moves and hitting the breaks: Owl journeys surprise researchers in western Montana

PKU Scientists simulate the origin and evolution of the North Atlantic Oscillation

ICRAFT breakthrough: Unlocking A20’s dual role in cancer immunotherapy

How VR technology is changing the game for Alzheimer’s disease

A borrowed bacterial gene allowed some marine diatoms to live on a seaweed diet

Balance between two competing nerve proteins deters symptoms of autism in mice

Use of antifungals in agriculture may increase resistance in an infectious yeast

Awareness grows of cancer risk from alcohol consumption, survey finds

[Press-News.org] Mapping the optimal route between two quantum states
Experiment measures millions of quantum trajectories to predict 'most likely' route