Bright Horizons #17 — Seminars

• • • QUANTUM: BENJAMIN SCHUMACHER, PH.D. • • •

The Private Lives of Quantum Particles

Quantum physics is famously weird. Quantum systems can exhibit all sorts of bizarre behavior, from the interference of probability waves to the almost-telepathic connection called quantum entanglement. But it turns out that many of these phenomena can only be observed under conditions of the strictest privacy, in which the systems are “informationally isolated” from the rest of the world.

• Quantum interference only occurs if a particle leaves no trace of its path through the experiment.
• It is impossible to exactly “clone” the information encoded in a quantum particle.
• The relationship between two entangled particles is "monogamous" — if A is entangled with B, then A cannot be entangled with C, or D, or anything else.

These are not accidental features of quantum theory. They are inescapable facts about the microscopic world, and they point to a profound principle of nature: Quantum physics is what happens when nobody is looking.

Here are the slides (1mb file).

2π Is Not Zero (But 4π Is)

If you rotate any geometrical shape by 360 degrees (2π radians) about any axis, you will end up with exactly the same shape. But this fact, seemingly obvious, is not true for quantum particles with spin. Learn how a rotation by 2π actually makes a big difference, and how it all comes down to a simple minus sign — probably the most important minus sign in all of physics. On this sign depends everything from the laws of chemistry to the solidity of matter.
            Note: Though we will grapple with deep concepts of geometry and quantum physics, our discussion should be accessible to anyone who lives in three-dimensional space.

Here are the slides (4mb file).
Here are the videos (22mb file)

The Physics of Impossible Things

Some things can happen in our Universe; others cannot. The laws of physics establish the boundary between possibility and impossibility. Physicists naturally spend most of their time thinking about the possible, but it is surprising useful on occasion to think about the impossible as well. In this seminar, we will make a brief reconnaissance across the frontier to study a variety of impossible things. We will encounter standard science-fiction gadgets like time machines and faster-than-light spaceships — as well as other, less-familiar prodigies like quantum cloners and bounded electromagnetic miracles. We will discover some surprising principles at work. Venture into the study of impossible things and come away with an affirmation of the consistent logic of nature, and renewed wonder at real phenomena.

Here are the slides (2mb file).

The Force That Isn’t a Force

What makes a rubber band elastic? This seemingly simple question has a wonderful and bizarre answer, first discovered in the 1930’s. The stretchiness of rubber is the result of its entropy, the microscopic disorder of its molecules. Now, decades later, this idea may provide a clue to the most familiar and mysterious of the basic forces of nature: gravity. As we explore the link between entropy and gravity, we will discuss forces that are not really forces, bodies that get colder when you heat them up, and black holes that are not quite black. We will probe the ultimate source of order in the cosmos. And we will encounter some of the most fascinating and unexpected insights of contemporary theoretical physics.

Here are the slides (4mb file).
Here are the videos (15mb file)

• • • ASTROPHYSICS: CHRISTOPHER IMPEY, PH.D. • • •

How It Began

We’ll explore the amazing story of cosmic creation, where enough matter to form 100 billion galaxies emerged from a super-hot and super-dense iota of space-time 13.7 billion years ago. The universe is driven by dark energy and sculpted by dark matter, both of which present challenges to current understanding. Observations probe back to within the first tiny fraction of a second after the big bang. Modern cosmology seeks to answer the fundamental question: where did it all come from and how did it begin?

Here are the slides (19mb file).

The Search for Habitable Worlds

Twenty years ago, no planets were known outside the Solar System. Currently, the search for exoplanets is one of the most exciting fields in science, with new discoveries almost daily and a body count of over 3,000. The methods for finding and characterizing exoplanets will be discussed, along with a summary of the exoplanet “zoo” and the prospects for the detection of Earth clones. The frontier of this research is a search for biomarkers, chemical traces of biology on a remote world.

Here are the slides (11mb file).

Life on Earth and Elsewhere

A singular attribute of this planet is biology, yet the universe is in many ways made for life and there’s an expectation that biology may be abundant. Starting with the characteristics and extremes of life on Earth, we’ll look at the prospects for the existence of life elsewhere. Transitioning from hard science to the realm of speculation, we are driven to explore the consequences of biological evolution and the development of technology, and ask the question: how strange might life in the universe be?

Here are the slides (7mb file).

Feeding the Beast: Supermassive Black Holes in the COSMOS Survey

Recent research has shown that every galaxy harbors a supermassive black hole, but the factors controlling their growth and activity are not well understood. The Cosmological Evolution Survey (COSMOS) is the largest contiguous region of the sky ever imaged by the Hubble space Telescope. While it was motivated by the study of galaxy evolution and morphology, the combination of depth, breadth, and extensive multi-wavelength data makes it the best region in the sky for a comprehensive study of Active Galactic Nuclei (AGN). This talk will characterise the zoo of AGNs as seen in the COSMOS volume. The complete census tells a tantalizing story about the co-evolution of galaxies and black holes in the distant universe.

Here are the slides (4mb file).

• • • NEUROBIOLOGY: ROBERT SAPOLSKY, PH.D. • • •

The Biology of Memory

If we lose our sight, if we are crippled by an accident, if we are bed-bound because of heart disease, our lives are greatly compromised. But if we lose our memories, we lose our very selves. Consider the biology of memory with Dr. Sapolsky. We’ll cover the basics of the neurobiology of different types of memory, ranging from the pertinent regions of the brain down to the pertinent molecules and genes. Examine some of the most impressive features of memory along with its wild inaccuracies in surprising circumstances. Learn how memory fails in some of the neurological diseases that most terrify us, including diseases of an excess of memory. Look at the modulators of memory — hormones, emotional state, and diet. Identify the key area of individual differences in memory skills, where do the differences come from, and what you can do to improve your own memory capacities.

Here are the slides (12mb file).

Sushi and Middle Age

When was the last time you ate a really different, type of food; listened to a new genre of music; or made a substantial change in my appearance? By asking the question, “How did I become the sort of person who, when watching late night TV, buys anthologies of music I was listening to when I was in college?”, Dr. Sapolsky examines the phenomenon that as we age, we get less interested in novelty and increasingly crave the familiar. He covers some of his own off-the-beaten path research on the subject, and then considers the science underlying this age-related effect. This includes neurobiology — and the good news that our brains don’t fall apart with age anywhere near as much as researchers used to think, and that there are substantial differences between chronological and psychological age. We’ll search anthropology for clues to the role of novelty — for example, the impact of a grandmother on infant survival among hunter-gatherers. And even zoology is touched on — how after an adolescence of openness to novelty, even mice and monkeys become less willing to eat a new type of food by early adulthood. We are not alone in always ordering the same favorite meal off the menu. As is your habit, get the details on the interplay of novelty and age.

Humans: Are We Just Another Primate? Are We Just a Bunch of Neurons?

Prof. Sapolsky divides his time between doing neurobiology research in the lab, and research on wild baboons in East Africa. In this lecture, he considers human nature from these two perspectives. As we consider human violence, empathy, theory of mind, competition, personality, and creativity, are we just another primate, merely on a continuum with all the others, or are we intrinsically special? Naturally, the answer is a mixture of both, where over and over, we share the same basic behaviors and underlying biology with the other primates, but then use them in ways that are utterly unique.
            Next, we’ll look at the fact that just as in a mouse, a frog, and a housefly, our behaviors emanate from the nervous system, a collection of neurons. Some provocative findings emerge from the study of the normal and abnormal functioning of the nervous system: a type of epilepsy in which a person develops a particular style of religiosity; brain damage that produces a person who knows the difference between right and wrong, yet cannot act on it; a disease in which a single gene is mutated leading to what appears to be the most florid mild life crisis imaginable; a parasite that, when infecting the brain, makes people less fearful and more reckless; and a response of the immune system to a childhood fever that makes someone more likely to obsessively count numbers. Take a tour of the unlikely ways in which the nervous system functions and malfunctions and entertain a challenge to the very notion of free will.

Here are the slides (8mb file).

The Biology of Aggression and Violence

You don’t need to get up on a soapbox to convince people that, ranging from a mugging to a mushroom cloud, the threat of violence menaces our lives. Dr. Sapolsky considers the biology of violence, dealing with a single fact that makes this one of the most complicated subjects in behavioral biology — we don’t hate violence. In fact, at times, we love it — we pay money to watch it, barely restrain ourselves from jumping in, glorify, and reward our experts at it. What we hate is violence in the wrong context, a very different proposition.
            Delve into the biology of violence, beginning with what happens in the brain a second before a person commits a violent act, to considering factors influencing that neurobiology, stretching all the way back to the selective pressures that mediated the evolution of violence over the course of millions of years. Along the way, you’ll find some good news. For example, while some very visceral parts of our brains are prone to divide the world into Us and Them (and to not much like the latter), we can be manipulated into changing Us/Them dichotomies very rapidly. And how a hormone renowned for its ability to promote violence, namely testosterone, actually has far less to do with it than typically thought. We’ll see how evolutionary biology and game theory help explain circumstances where cooperation arises in the most unlikely places. Join the discussion and make more sense of violence and aggression.

Here are the slides (8mb file).

• • • CHEMISTRY: ROBERT HAZEN, PH.D. • • •

Genesis: The Scientific Quest for Life’s Origins

Is life’s origin an inevitable process throughout the cosmos, or is it an improbable accident, restricted to a few planets (or only one)? How does a lifeless geochemical world of oceans, atmosphere, and rocks transform into a living planet? Find out how scientists use experimental and theoretical frameworks to deduce the origin of life.

Here are the slides (31mb file).

The Diamond Makers

Diamond forms deep in Earth when carbon experiences searing heat and crushing pressure. Decades ago General Electric scientists learned how to mimic those extreme conditions of Earth’s interior in the laboratory to make synthetic diamonds. Learn the human drama and techological advances involved in producing this coveted gem and industrial tool from carbon-rich substances.

Here are the slides (7mb file).

The Story of Earth: How the Geosphere and Biosphere Co-evolved

Earth is a planet of frequent, extravagant change. Its near-surface environment has transformed over and over again across 4.5 billion years of history. Learn about the work of Dr. Hazen and colleagues that suggests that Earth’s living and nonliving spheres have co-evolved over the past four billion years.

Here are the slides (39mb file).

Chemical Bonding

The solid, liquid, and gaseous materials around us depend on the specific elements involved and the chemical bonds that hold those atoms together. By looking at the nature and significance of ionic, metallic, and covalent bonds you’ll gain a new understanding of the workings of the world around you.

Here are the slides (7mb file).

• • • ARCHAEOLOGY: KENNETH HARL, PH.D. • • •

From Old Europe to Roman Provinces

Explore the prehistoric foundations of Scandinavia and the Viking Age from ca. 3000 B.C. to 400 A.D. We start with the Megalithic cultures of the Neolithic period (think Stonehenge), then the arrival of Indo-Europeans into Scandinavia by 2300 B.C. (with new archaeological wares and the dairy culture), then the Northern Bronze Age (1750–1100 B.C.). We follow with the Celtic and Roman contributions in the Iron Age. In this seminar learn the unique environmental, cultural, and social factors that created a context for the Vikings

Here are the slides (18mb file).

Great Halls and Market Towns in Viking Age Scandinavia

Using archaeology and literary sources (especially saga and poems of the Eddas), learn how the “great halls” emerged as the main focus of Scandinavia civilization in 400–1100. From these halls issued the dreaded sea kings and jarls (or earls) of the Viking Age. Find out how the development of towns facilitated commerce along the “Northern Trade Arc,” stretching from Dublin to Constantinople. Towns such as Birka and Hedeby were vital for the transformation and economic, social, technological advance of Scandinavian society in the Viking Age.

Here are the slides (19mb file).

Ships and Ship Building in the Viking Age

European historians record the effectiveness of the fearsome Viking longship; learn about the features and technologies that made it so. Based on archaeological finds, you will also learn about the multi-millennial evolution of the longship and knarr (cargo ship), from linden to oak, dugout to mast and sail. Gain an appreciation for the form and function, as well as the wider implications of Norse naval mastery for exploration and settlement overseas.

Here are the slides (33mb file).

Warfare in the Viking Age

For three centuries the Vikings, propelled by a heroic ethos of their war gods, dominated the battlefield by their tactics and weapons. Discover what other factors made the Vikings accomplished warriors. Learn what archaeological finds tell us about warfare. Scandinavian sea kings and their warriors rewrote the political geography of Europe, and forged the three Scandinavian kingdoms that have endured to this day.

Here are the slides (30mb file).