From University of California-Berkeley (US) via Live Science (US): “1st ‘atom tornado’ created from swirling vortex of helium atoms”

From University of California-Berkeley (US)

via

Live Science (US)

9.14.21
Ben Turner

The beams could be used to peak at unseen subatomic details.

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An artist’s depiction of a swirling vortex beam. (Image credit: Weiquan Lin via Getty Images)

Physicists have created the first-ever atomic vortex beam — a swirling tornado of atoms and molecules with mysterious properties that have yet to be understood.

By sending a straight beam of helium atoms through a grating with teeny slits, scientists were able to use the weird rules of quantum mechanics to transform the beam into a whirling vortex.

The extra gusto provided by the beam’s rotation, called orbital angular momentum, gives it a new direction to move in, enabling it to act in ways that researchers have yet to predict. For instance, they believe the atoms’ rotation could add extra dimensions of magnetism to the beam, alongside other unpredictable effects, due to the electrons and the nuclei inside the spiraling vortex atoms spinning at different speeds.

“One possibility is that this could also change the magnetic moment of the atom,” or the intrinsic magnetism of a particle that makes it act like a tiny bar magnet, study co-author Yair Segev, a physicist at the University of California, Berkeley, told Live Science.

In the simplified, classical picture of the atom, negatively-charged electrons orbit a positively-charged atomic nucleus. In this view, Segev said that as the atoms spin as a whole, the electrons inside the vortex would rotate at a faster speed than the nuclei, “creating different opposing [electrical] currents” as they twist. This could, according to the famous law of magnetic induction outlined by Michael Faraday, produce all kinds of new magnetic effects, such as magnetic moments that point through the center of the beam and out of the atoms themselves, alongside more effects that they cannot predict.

The researchers created the beam by sending helium atoms through a grid of tiny slits each just 600 nanometers across. In the realm of quantum mechanics — the set of rules which govern the world of the very small — atoms can behave both like particles and tiny waves; as such, the beam of wave-like helium atoms diffracted through the grid, bending so much that they emerged as a vortex that corkscrewed its way through space.

The whirling atoms then arrived at a detector, which showed multiple beams — diffracted to differing extents to have varying angular momentums — as tiny little doughnut-like rings imprinted across it. The scientists also spotted even smaller, brighter doughnut rings wedged inside the central three swirls. These are the telltale signs of helium excimers — a molecule formed when one energetically excited helium atom sticks to another helium atom. (Normally, helium is a noble gas and doesn’t bind with anything.)

The orbital angular momentum given to atoms inside the spiraling beam also changes the quantum mechanical “selection rules” that determine how the swirling atoms will interact with other particles, Segev said. Next, the researchers will smash their helium beams into photons, electrons and atoms of elements besides helium to see how they might behave.

If their rotating beam does indeed act differently it could become an ideal candidate for a new type of microscope that can peer into undiscovered details on the subatomic level. The beam could, according to Segev, give us more information on some surfaces by changing the image that is imprinted upon the beam atoms bounced off it.

“I think that as is often the case in science, it’s not a leap of capability that leads to something new, but rather a change in perspective,” Segev said.

The researchers published their findings Sept. 3 in the journal Science.

See the full article here .

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The University of California-Berkeley US) is a public land-grant research university in Berkeley, California. Established in 1868 as the state’s first land-grant university, it was the first campus of the University of California (US) system and a founding member of the Association of American Universities (US). Its 14 colleges and schools offer over 350 degree programs and enroll some 31,000 undergraduate and 12,000 graduate students. Berkeley is ranked among the world’s top universities by major educational publications.

Berkeley hosts many leading research institutes, including the Mathematical Sciences Research Institute and the Space Sciences Laboratory. It founded and maintains close relationships with three national laboratories at DOE’s Lawrence Berkeley National Laboratory(US), DOE’s Lawrence Livermore National Laboratory(US) and DOE’s Los Alamos National Lab(US), and has played a prominent role in many scientific advances, from the Manhattan Project and the discovery of 16 chemical elements to breakthroughs in computer science and genomics. Berkeley is also known for student activism and the Free Speech Movement of the 1960s.

Berkeley alumni and faculty count among their ranks 110 Nobel laureates (34 alumni), 25 Turing Award winners (11 alumni), 14 Fields Medalists, 28 Wolf Prize winners, 103 MacArthur “Genius Grant” recipients, 30 Pulitzer Prize winners, and 19 Academy Award winners. The university has produced seven heads of state or government; five chief justices, including Chief Justice of the United States Earl Warren; 21 cabinet-level officials; 11 governors; and 25 living billionaires. It is also a leading producer of Fulbright Scholars, MacArthur Fellows, and Marshall Scholars. Berkeley alumni, widely recognized for their entrepreneurship, have founded many notable companies.

Berkeley’s athletic teams compete in Division I of the NCAA, primarily in the Pac-12 Conference, and are collectively known as the California Golden Bears. The university’s teams have won 107 national championships, and its students and alumni have won 207 Olympic medals.

Made possible by President Lincoln’s signing of the Morrill Act in 1862, the University of California was founded in 1868 as the state’s first land-grant university by inheriting certain assets and objectives of the private College of California and the public Agricultural, Mining, and Mechanical Arts College. Although this process is often incorrectly mistaken for a merger, the Organic Act created a “completely new institution” and did not actually merge the two precursor entities into the new university. The Organic Act states that the “University shall have for its design, to provide instruction and thorough and complete education in all departments of science, literature and art, industrial and professional pursuits, and general education, and also special courses of instruction in preparation for the professions”.

Ten faculty members and 40 students made up the fledgling university when it opened in Oakland in 1869. Frederick H. Billings, a trustee of the College of California, suggested that a new campus site north of Oakland be named in honor of Anglo-Irish philosopher George Berkeley. The university began admitting women the following year. In 1870, Henry Durant, founder of the College of California, became its first president. With the completion of North and South Halls in 1873, the university relocated to its Berkeley location with 167 male and 22 female students.

Beginning in 1891, Phoebe Apperson Hearst made several large gifts to Berkeley, funding a number of programs and new buildings and sponsoring, in 1898, an international competition in Antwerp, Belgium, where French architect Émile Bénard submitted the winning design for a campus master plan.

20th century

In 1905, the University Farm was established near Sacramento, ultimately becoming the University of California-Davis. In 1919, Los Angeles State Normal School became the southern branch of the University, which ultimately became the University of California-Los Angeles. By 1920s, the number of campus buildings had grown substantially and included twenty structures designed by architect John Galen Howard.

In 1917, one of the nation’s first ROTC programs was established at Berkeley and its School of Military Aeronautics began training pilots, including Gen. Jimmy Doolittle. Berkeley ROTC alumni include former Secretary of Defense Robert McNamara and Army Chief of Staff Frederick C. Weyand as well as 16 other generals. In 1926, future fleet admiral Chester W. Nimitz established the first Naval ROTC unit at Berkeley.

In the 1930s, Ernest Lawrence helped establish the Radiation Laboratory (now DOE’s Lawrence Berkeley National Laboratory (US)) and invented the cyclotron, which won him the Nobel physics prize in 1939. Using the cyclotron, Berkeley professors and Berkeley Lab researchers went on to discover 16 chemical elements—more than any other university in the world. In particular, during World War II and following Glenn Seaborg’s then-secret discovery of plutonium, Ernest Orlando Lawrence’s Radiation Laboratory began to contract with the U.S. Army to develop the atomic bomb. Physics professor J. Robert Oppenheimer was named scientific head of the Manhattan Project in 1942. Along with the Lawrence Berkeley National Laboratory, Berkeley founded and was then a partner in managing two other labs, Los Alamos National Laboratory (1943) and Lawrence Livermore National Laboratory (1952).

By 1942, the American Council on Education ranked Berkeley second only to Harvard University (US) in the number of distinguished departments.

In 1952, the University of California reorganized itself into a system of semi-autonomous campuses, with each campus given its own chancellor, and Clark Kerr became Berkeley’s first Chancellor, while Sproul remained in place as the President of the University of California.

Berkeley gained a worldwide reputation for political activism in the 1960s. In 1964, the Free Speech Movement organized student resistance to the university’s restrictions on political activities on campus—most conspicuously, student activities related to the Civil Rights Movement. The arrest in Sproul Plaza of Jack Weinberg, a recent Berkeley alumnus and chair of Campus CORE, in October 1964, prompted a series of student-led acts of formal remonstrance and civil disobedience that ultimately gave rise to the Free Speech Movement, which movement would prevail and serve as precedent for student opposition to America’s involvement in the Vietnam War.

In 1982, the Mathematical Sciences Research Institute (MSRI) was established on campus with support from the National Science Foundation and at the request of three Berkeley mathematicians — Shiing-Shen Chern, Calvin Moore and Isadore M. Singer. The institute is now widely regarded as a leading center for collaborative mathematical research, drawing thousands of visiting researchers from around the world each year.

21st century

In the current century, Berkeley has become less politically active and more focused on entrepreneurship and fundraising, especially for STEM disciplines.

Modern Berkeley students are less politically radical, with a greater percentage of moderates and conservatives than in the 1960s and 70s. Democrats outnumber Republicans on the faculty by a ratio of 9:1. On the whole, Democrats outnumber Republicans on American university campuses by a ratio of 10:1.

In 2007, the Energy Biosciences Institute was established with funding from BP and Stanley Hall, a research facility and headquarters for the California Institute for Quantitative Biosciences, opened. The next few years saw the dedication of the Center for Biomedical and Health Sciences, funded by a lead gift from billionaire Li Ka-shing; the opening of Sutardja Dai Hall, home of the Center for Information Technology Research in the Interest of Society; and the unveiling of Blum Hall, housing the Blum Center for Developing Economies. Supported by a grant from alumnus James Simons, the Simons Institute for the Theory of Computing was established in 2012. In 2014, Berkeley and its sister campus, Univerity of California-San Fransisco (US), established the Innovative Genomics Institute, and, in 2020, an anonymous donor pledged $252 million to help fund a new center for computing and data science.

Since 2000, Berkeley alumni and faculty have received 40 Nobel Prizes, behind only Harvard and Massachusetts Institute of Technology (US) among US universities; five Turing Awards, behind only MIT and Stanford; and five Fields Medals, second only to Princeton University (US). According to PitchBook, Berkeley ranks second, just behind Stanford University, in producing VC-backed entrepreneurs.

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