Seminars And Colloquia SEARCH:Hoxton

In 1964, when Thorne was a student, there were hints that our universe might have a Warped Side:  Objects and phenomena made from warped space and warped time instead of from matter.  Thorne and his colleagues have spent these past sixty years turning those hints into clear understanding.  They have explored the Warped Side through theory (using mathematics and computer simulations to probe what the laws of physics predict) and through astronomical observations (primarily with gravitational waves). In this lecture he will describe what they have learned about Warped-Side phenomena:  black holes, wormholes, gravitational waves, our universe’s big-bang birth, and the possibility of time travel.

The quantum laws governing atoms and other tiny objects seem to defy common sense, and information encoded in quantum systems has weird properties that baffle our feeble human minds. John Preskill will explain why he loves quantum entanglement, the elusive feature making quantum information fundamentally different from information in the macroscopic world. By exploiting quantum entanglement, quantum computers should be able to solve otherwise intractable problems, with far-reaching applications to cryptology, materials, and fundamental physical science. Preskill is less weird than a quantum computer, and easier to understand.

Entanglement is the strangest feature of quantum theory, often dubbed ''spooky action at a distance’’. Quantum entanglement can occur on a macroscopic scale with trillions of electrons, leading to "strange metals" and novel superconductors which can conduct electricity without resistance even at relatively high temperatures. Remarkably, related entanglement structures arise across the horizon of a black hole, and give rise to Hawking’s quantum paradox. This lecture will be designed to introduce these forefront topics in current physics research to a general audience.

The discovery of gravitational waves, predicted by Einstein in 1916, is enabling both important tests of the theory of general relativity, and represents the birth of a new astronomy. Modern astronomy, using all types of electromagnetic radiation, has giving us an amazing understanding of the complexities of the universe, and how it has evolved. Now, gravitational waves and neutrinos are beginning to provide the opportunity to pursue some of the same astrophysical phenomena in very different ways, as well as to observe phenomena that cannot be studied with electromagnetic radiation. The detection of gravitational waves and the emergence and prospects for this exciting new science will be explored.

In the four hundred years since Galileo, the physics community has constructed a remarkably successful mathematical description of the world around us.  From deep inside the atomic nucleus to the structure of the universe on the largest scales, from the flow air over the wing of an airplane to the flow of electrons in a computer chip, we can predict in detail what we see, and what will happen when we look in places we have never looked before.  What are the limits to this predictive power?  In particular, can we imagine a theoretical physicist’s approach to the complex and diverse phenomena of the living world?  Is there something fundamentally unpredictable about life, or are we missing some deep theoretical principles that could bring the living world under the predictive umbrella of physics?  Exploring this question gives us an opportunity to reflect on what we expect from our scientific theories, and on many beautiful phenomena.  I hope to leave you with a deeper appreciation for the precision of life’s basic mechanisms, and with optimism about the prospects for better theories. 

In 2016, scientists announced the first ever detection of gravitational waves from colliding black holes, launching a new era of gravitational wave astrophysics. Gravitational waves were predicted by Einstein a hundred years earlier. I will describe the science, technology, and human story behind these discoveries that provide a window into some of the most violent and warped events in the Universe.

 

Many complex phenomena are so familiar that we hardly realize that they defy our normal intuition.  Examples include the anomalous flow of granular material, the long messy tendrils left by honey spooned from one dish to another, the pesky rings deposited by spilled coffee on a table after the liquid evaporates or the common splash of a drop of liquid onto a countertop.  Aside from being uncommonly beautiful to see, many of these phenomena involve non-linear behavior where the system is far from equilibrium.  Although most of the world we know is beyond description by equilibrium theories, we are still only at the threshold of learning how to deal with such deep and complex behavior.  Thus, these are phenomena that can lead the inquisitive into new realms of physics.

Inflationary cosmology gives a plausible explanation for many observed features of the universe, including its uniformity, its mass density, and the patterns of the ripples that are observed in the cosmic microwave background. Beyond what we can observe, most versions of inflation imply that our universe is not unique, but is part of a possibly infinite multiverse. I will describe the workings of inflation, the evidence for inflation, and why I believe that the possibility of a multiverse should be taken seriously.

This talk will discuss the opportunities for the exploration of physical systems that have not heretofore existed in the natural world.

New developments in particle physics offer a new and radically simple conception of the universe. Fundamental particles called quarks and leptons make up everyday matter, and two new laws of nature rule their interactions. Until July 4, 2012, our neat story was missing one piece, a particle called the Higgs boson. Without it, there would be no atoms, no chemistry, no liquids or solids, and no basis for life. Why did thousands of physicists devote decades to the hunt, and how does the “discovery of the century” change the way we see the world?

The National Ignition Facility (NIF), at Lawrence Livermore National Laboratory in Livermore, California, is the world’s most energetic laser system. NIF is capable of producing over 1.8 MJ and 500 TW of ultraviolet light, 100 times more than any other operating laser. Completed in March 2009, it is maturing rapidly and transitioning into the world’s premier high-energy-density science experimental facility, while supporting its strategic security, fundamental science, and energy security missions.

By concentrating intense laser energy into target only millimeters in length, NIF can, for the first time, produce conditions emulating those found in planetary interiors and stellar environments and creating fusion energy to power our future. The extreme conditions of energy density, pressure, and temperature will enable scientists to pursue fundamental science experiments designed to address a range of scientific questions, from observing new states of matter to exploring the origin of ultrahigh-energy cosmic rays. Early experiments have been successfully completed in support of materials equations of state, materials strength, and radiation transport in extreme temperature and pressure conditions.

The National Ignition Campaign, an international effort pursued on the NIF, aims to demonstrate fusion burn and generate more energy output than the laser energy delivered to the target. Achieving this ignition goal will validate the viability of inertial fusion energy (IFE) as a clean source of energy. A laser-based IFE power plant will require advances in high-repetition-rate lasers, large-scale target fabrication, target injection and tracking, and other supporting technologies. These capabilities could lead to an operational prototype IFE power plant in 10 to 15 years. LLNL, in partnership with academia, national laboratories, and industry, is developing a Laser Inertial Fusion Energy (LIFE) baseline design concept and examining technology choices for developing a LIFE prototype power plant.

This talk will describe the unprecedented experimental capabilities of the NIF, its role in strategic security and fundamental science, and the pathway to achieving fusion ignition to create a clean and secure energy future.

Professor Richter is the co-winner of the 1976 Nobel Prize in physics for the discovery of the J/Ψ particle which was the first observation of a particle containing a fourth quark named the charm quark and was a central part of the so-called November revolution of particle physics. He has accumulated many other honors in his career including a long tenure as the director of Stanford Linear Acceleratory Laboratory from 1984 to 1999. He has also been the recipient of the E.O. Lawrence Medal, has served as president of the American Physical Society, and is a member of the National Academy of Sciences. He presently serves on the board of directors of Scientists and Engineers for America, an organization focused on promoting sound science in American government and is a Senior Fellow by Courtesy of the Center for Environmental Science and Policy at Stanford Institute for International Studies. In the past several years Professor Richter has turned his attention to the central problem of the 21st century, the effect of human activity on the global climate. He has written a book with the same title as his lecture.

The history of the universe in a nutshell, from the Big Bang to now, and on to the future – John Mather will tell the story of how we got here, how the Universe began with a Big Bang, how it could have produced an Earth where sentient beings can live, and how those beings are discovering their history. Mather was Project Scientist for NASA’s Cosmic Background Explorer (COBE) satellite, which measured the spectrum (the color) of the heat radiation from the Big Bang, discovered hot and cold spots in that radiation, and hunted for the first objects that formed after the great explosion. He will explain Einstein’s biggest mistake, show how Edwin Hubble discovered the expansion of the universe, how the COBE mission was built, and how the COBE data support the Big Bang theory. He will also show NASA’s plans for the next great telescope in space, the James Webb Space Telescope. It will look even farther back in time than the Hubble Space Telescope, and will look inside the dusty cocoons where stars and planets are being born today. Planned for launch in 2013, it may lead to another Nobel prize for some lucky observer.

This constant acted as a sort of anti-gravity to counteract the force of gravity that would otherwise be pulling the masses of the universe together. When astronomers such as Hubble and others subsequently observed the red shifts of far distant stars and galaxies, they discovered that the universe is not static but, indeed, is expanding. Therefore, it no longer seemed necessary to have a counter balance to gravity. It is said that Einstein, when he heard of the expansion of the universe, characterized his use of a cosmological constant his greatest mistake. Indeed, for the better part of 100 years the standard view of the universe was that its expansion rate was gradually slowing down under the influence of the gravity of its components. The question of the future of the universe was posed in terms of, depending on the total mass of the universe, whether the universe would come to a stop and fall back in on itself, come to a halt at infinite time, or continue to expand forever. Professor Perlmutter and his colleagues, using Supernovas Type Ia as “standard candles” because of their great brightness, have measured the expansion rate of the universe at much large distances than previously possible. In doing so, they have made the remarkable discovery that the expansion of the universe is actually accelerating. There appears to be a previously undetected force of nature that acts like antigravity, dominating the gravitational force and causing the universe to expand faster and faster with time. So the better part of a century after the cosmological constant was abandoned, it seems that it must be re-employed to describe this new phenomenon which has been labeled dark energy. Perhaps Einstein was right after all!