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At least 19 records

Fusion and Fission Energy and Science Directorate and Information Technology Services Directorate HPC Cluster Reduction, Consolidation, and Savings in Data Center Space, Power, and Cooling

This report evaluates the benefits of decommissioning six legacy FFESD purchased HPC clusters and consolidating services and workloads into a new HPC cluster named HELIOS. The findings demonstrate significant reductions in the data center power and cooling requirements, data center footprint, and operational overhead, while simultaneously increasing computational capacity.

97 MATHEMATICS AND COMPUTING↗

Phonon-induced rotation of the electronic nematic director in superconducting Bi 2 Se 3

The doped topological insulator A x Bi 2 Se 3 , with A = {Cu,Sr,Nb}, becomes a nematic superconductor below T c ≈ 3–4 K. The associated electronic nematic director is described by an angle α and is experimentally manifested in the elliptical shape of the in-plane critical magnetic field H c2 . Because of the threefold rotational symmetry of the lattice, α is expected to align with one of three high-symmetry directions corresponding to the in-plane nearest-neighbor bonds, consistent with a Z 3 -Potts nematic transition. Here, we show that the nematic coupling to the acoustic phonons, which makes the nematic correlation length tend to diverge along certain directions only, can fundamentally alter this phenomenology in trigonal lattices. Compared to hexagonal lattices, the former possesses a sixth independent elastic constant c14 due to the fact that the in-plane shear strain doublet (ε xx – ε yy , – 2ε xy ) and the out-of-plane shear strain doublet (2ε yz , – 2ε zx ) transform as the same irreducible representation. We find that, when c 14 overcomes a threshold value, which is expected to be the case in doped Bi 2 Se 3 , the nematic director α unlocks from the high-symmetry directions due to the competition between the quadratic phonon-mediated interaction and the cubic nematic anharmonicity. This implies the breaking of the residual in-plane twofold rotational symmetry (C 2x ), resulting in a triclinic phase. Furthermore, we discuss the implications of these findings for the structure of nematic domains, for the shape of the in-plane H c2 in A x Bi 2 Se 3 , and for the presence of nodes inside the superconducting state.

75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND↗

Associate Laboratory Directorate for Weapon Physics (ALDX) [Slides]

ALDX is one of seven technical Directorates at the Laboratory and resides within the Weapons Program. The Weapons Physics Directorate stewards a number of critical capabilities to meet its mission. Our mission is to sustain the resilience of the US nuclear stockpile and help shape a globalized nuclear world. Sustaining the aging stockpile poses scientific challenges to assess and certify the stockpile without testing. We are helping to solve major technical challenges in the nuclear global security regime. Geopolitical realities demand the Laboratory’s excellence in providing solutions to national security problems. High Performance Computing at Los Alamos opens the doors to many sophisticated modeling techniques. We use many experimental facilities to probe weapons physics. The diverse skill set required to execute ALDX’s mission has benefited greatly from the Postdoc program.

45 MILITARY TECHNOLOGY, WEAPONRY, AND NATIONAL DEF↗

Did you know the Lab and its first director share a birthday month? A look back at Oppenheimer’s wartime legacy through historical items in our collections

Many birthdays ago, at only 38 years old and with no previous administrative experience, J. Robert Oppenheimer accepted responsibility for a national security mission of unprecedented scale. His charge, handed down by Manhattan Project director General Leslie R. Groves, was to lead a team of the world’s foremost scientific minds in developing the first atomic bomb. Under Oppenheimer’s leadership, a community of over 6,000 scientists, engineers, and other personnel living and working at the top-secret lab in Los Alamos completed their task in only 27 months, delivering the world’s first two atomic weapons to the U.S. military. In honor of what would have been Oppenheimer’s 119th birthday (on April 22), the National Security Research Center remembers his contributions as an administrator and scientist and the scope of his legacy as the first director of the Lab through items in our unclassified collections.

99 GENERAL AND MISCELLANEOUS↗

Attend debut of new film on the Lab’s first director

The NSRC’s much-anticipated documentary, Oppenheimer: Science, Mission, Legacy, will premiere for Lab staff later this summer at the NSSB auditorium, and then be made available online. Speakers at the premiere will include film creator and primary producer Dave Tietmeyer (Multimedia Services, CEA-MP), Senior Historian Alan Carr (WRS-NSCMS), and NSRC Director Brye Steeves (WRS-DO). The film was entirely produced by the NSRC and Laboratory staff and will commemorate former director J. Robert Oppenheimer and his endeavors. Much of the material and several scenes featured in the film are based on collections from the Manhattan Project era and interviews with today’s Lab staff and Oppenheimer experts.

99 GENERAL AND MISCELLANEOUS↗

Watch it again-or for the first time: Panel discussion and Q&A on First Lab Director J. Robert Oppenheimer

On June 19, 2023, at the National Security Sciences Building (NSSB) auditorium, LANL Director Thom Mason, LANL physicist Anna Llobet, American Prometheus author Kai Bird, and retired Senate staff member Tim Rieser discussed the life, work and legacy of first Lab Director J. Robert Oppenheimer. The panel event was moderated by LANL senior historian Alan Carr.

99 GENERAL AND MISCELLANEOUS↗

Need something worthwhile to read and watch? The Lab’s classified library director, senior historian’s offer recommendations

Social distancing has many of us turning even more to our streaming services and e-bookshelves in our free time. But if you’re looking for something even more compelling than Tiger King, staff from the National Security Research Center (the Lab’s classified library) have some recommendations for you. NSRC Director Riz Ali and Senior Historian Alan Carr share their top picks of books and movies on Los Alamos and atomic bomb history.

45 MILITARY TECHNOLOGY, WEAPONRY, AND NATIONAL DEF↗

Listen: Oppenheimer’s office chair one of the only possessions the lab has from our first director

Even the father of the atomic bomb had to sit down somewhere. It's hard to believe that our legendary first Lab director and brilliant physicist J. Robert Oppenheimer did something as ordinary as using a chair at work like the rest of us do. However, aside from a recently gifted book, this chair from the 1940s is the only Oppenheimer possession that the Lab has. And Oppie fans love it. The chair is routinely loaned to museums nationwide for display.

99 GENERAL AND MISCELLANEOUS↗

LANL Weapons Physics Directorate: Mission Scope and Opportunities [Slides]

The Weapons Physics Directorate stewards a number of critical capabilities to meet the LANL mission. To execute our mission, ALDX develops and applies cutting-edge theory, computational models and multi-physics simulation codes, and designs, executes, and analyzes complex experiments. Our mission is to sustain the current stockpile, provide future stockpile options, and help shape a globalized nuclear world.

45 MILITARY TECHNOLOGY, WEAPONRY, AND NATIONAL DEF↗

‘Spokesperson for everyone at the Laboratory who believed in Oppenheimer’ Los Alamos physicist Fred Ribe’s 1954 petition protested former Lab Director’s revoked clearance

In 1953, J. Robert Oppenheimer received an ultimatum. The Atomic Energy Commission (AEC) sent the "father of the atomic bomb" and former Los Alamos Director a letter outlining two options: give up his Q clearance and role as advisor or appear before a board to prove that he wasn’t a threat to national security. Oppenheimer chose the latter. The ensuing saga that unfolded throughout 1954 peaked with a four-week, closed-door hearing in April and May after which Oppenheimer’s security clearance was formally revoked. The long, complex affair consisted of national security concerns, a tangle of questionable charges, divided opinions, loyalties, egos, and vendettas. AEC Chairman Lewis L. Strauss and Oppenheimer were at the center of events, though an important part of the historical record is Fred L. Ribe and the 493 other Los Alamos scientists who risked harming their careers to protest Oppenheimer’s ordeal. Ribe wrote a one-page letter, signed by his colleagues, to President Dwight Eisenhower and the AEC commissioners “objecting the decision and the grounds for it” as Ribe later wrote. This petition – and Strauss’s written response – were donated by Ribe and are part of the unclassified historical collections in the National Security Research Center, which is the Lab’s classified library.

96 KNOWLEDGE MANAGEMENT AND PRESERVATION↗

Former Director Sig Hecker to present classified colloquium on the end of nuclear testing

Hecker is a professor emeritus (research) in the Department of Management Science and Engineering and a senior fellow emeritus at the Freeman Spogli Institute for International Studies (FSI) at Stanford University. He served as the Lab’s fifth director from 1986 to 1997 and is a Los Alamos National Laboratory Medal recipient. He is an internationally recognized expert in plutonium science, global threat reduction and nuclear security with wide research interests covering nuclear weapons policy, nuclear security, and the safe and secure expansion of nuclear energy.

99 GENERAL AND MISCELLANEOUS↗

Weapons Engineering Directorate (ALDW) Overview [Slides]

The "Weapons Engineering Directorate (ALDW) Overview" is a presentation for recruiting purposes to be delivered at various colleges, universities, conferences, and professional organizations. The presentation provides prospective applicants with information about LANL, ALDW, and employee benefits.

42 ENGINEERING↗

Start your career at Los Alamos National Laboratory in the Associate Laboratory Directorate for Weapons Production [Slides]

Los Alamos National Laboratory (LANL) is the place for early-career professionals to join our crucial mission in support of national security. In the Associate Laboratory Directorate for Weapons Production (ALDWP) you will find a diverse workplace with roles of all kinds and endless upward momentum for a long-lasting and ever-changing career!

45 MILITARY TECHNOLOGY, WEAPONRY, AND NATIONAL DEF↗

Los Alamos National Laboratory Director's Strategic Resilience Initiative

The Director’s Strategic Resilience Initiative was created late in 2019 in recognition of the changing geo-political climate. The renewed strategic competition between Russia, China, and the United States, noted in the 2018 National Defense Strategy and the 2018 Nuclear Posture Review, put great power rivalry and competition at the forefront of national security considerations. At the same time, Russian President Vladimir Putin’s March 1, 2018, speech and China’s October 1, 2019, National Day Military Parade, underscored the nuclear dimensions of this new strategic competition. Accompanying this changed strategic environment are rapid advances in an expansive array of relevant technological sectors including affordable and comprehensive global communication and reconnaissance assets, autonomous vehicles, quantum computing, advanced manufacturing, and artificial intelligence.

99 GENERAL AND MISCELLANEOUS↗