As a postdoc you have the craziest job in the world.

You get your PhD with honors at one of the best universities, and at the same time they kick you out. You apply everywhere in the world, and you have not the faintest clue on which continent or in which time zone you will end up. Then you get a new job at a different university, and you can come and go whenever you want and do what ever you want. You can just think about the most esoteric questions that come to your mind: What is all matter...

Three-thousand-year rewind: It was the ancient Greeks who began to consider the world as an object and who undertook its first rational analysis. It was they who laid the foundation for the scientific method and the Western worldview. It seems, however, that the Greeks also suffered from a divorce of ego and world, of subject and object. Deeply hidden in their souls, it seems, was the need to perpetuate some portal to the ecstatic feel of the unity of everything that exists, of all being. As the German philosopher Friedrich Nietzsche enthused in the nineteenth century: “Did those centuries when...

A major breakthrough in the story of quantum physics begins with a young man holed up in a rain pipe—in order to find a quiet place for reading. It is the year 1919, in Munich, shortly after the end of World War I. The chaotic rioting in the streets that followed the revolution driving the German emperor out of office has finally calmed down, and now eighteen-year-old Werner Heisenberg can find some leisure time again.¹ He had been working as a local guide, assisting a vigilante group that was trying to reestablish order in the city, but now he...

Physics is like surfing. Or like an LSD trip.

The first time I had a peculiar feeling of enlightenment was when I was staring onto a white surface sprinkled with tiny black dots. I was fourteen years old and, during an extensive study of my father’sPlayboycollection, I had developed a taste for modern and underground literature like Charles Bukowski, the Beat Generation, and Ernest Hemingway. While looking for new interesting books in my parents’ bookcase, I stumbled upon Bertrand Russell’s super-sized volume,A History of Western Philosophy,and, just a few pages into it, a captivating picture.¹ The...

For forty years the tribes of Israel wandered through the desert, escaping slavery and genocide in ancient Egypt, before Moses led them to the Holy Land. When they arrived on the banks of the river Jordan, Moses climbed up Mount Nebo to die there. But before he died, he enjoyed a last glance into the country where his descendants were about to settle: a good land and large, abundant with grapes, figs, and pomegranates—a land flowing with milk and honey.¹

Just like the tribes of Israel, particle physicists have been on a quest for forty years now, with physicists...

What is the origin of the world’s diversity, the endless complexity of our surroundings, if everything is made out of a single primary type of particle and held together by a single primary type of force? The concept that solved this problem was first discovered in solid-state physics, and it is reminiscent of an old Irish legend (as found in the description of the piano pieceVoice of Lirby Henry Cowell): “Lir of the half tongue was the father of the gods, and of the universe. When he gave the orders for creation, the gods who executed his commands...

Among all elementary particles, the neutrino is surely the most exotic: Although sixty billion neutrinos pass every second through each square centimeter of the surface of the earth—as well as through every human body, or any other object—these particles penetrate through us and the whole earth’s interior as if through thin air. And although every single neutrino weighs less than one millionth the weight of the tiny electron (which itself is 10⁻²⁷grams!), they are so abundant that altogether they contribute about as much mass to the universe as all the stars combined. And, in addition, nobody knows...

In 1994 I was thrown into a world of madmen, dreamers, and visionaries, a heterogeneous bunch of nuclear and particle physicists, astrophysicists, chemists, and engineers who, far away from their original areas of expertise, were setting off on a quest for the neutrino. In the fall of that year I had passed my diploma exam (the German equivalent of the MSc) more poorly than well and was now looking for an interesting research topic for my dissertation. I knew more or less what I wanted: I was fascinated by the possibility of uncovering symmetries in the fundamental laws of nature....

Beyond any doubt this experiment was a monster. A thousand meters below the rock of a holy mountain in Japan, more than ten thousand electronic eyes would peer into a tank as broad as a ballroom and as high as a ten-story building, filled with 50,000 tons of ultra-pure water (see Fig. 9.1). What the eyes were looking for were bluish flashes of light. These flashes occur when a neutrino from the sun or the atmosphere collides with an electron in one of the water molecules, accelerating it to a speed greater than the speed at which light travels in...

Maybe it was pigeon droppings? What was it that created this infuriating “noise” seemingly coming from all directions? Radio noise that seriously jeopardized the measurement of the galactic radio flux by the two radio astronomers Arno Penzias and Robert Wilson.¹

An enamored pair of pigeons had chosen to nest, of all possible places, in the reflector of the radio antenna that Penzias and Wilson had gotten hold of from the Bell Telephone Laboratories. But even after the birds had been driven away—a tremendously difficult task—and the reflector had been cleaned, the problem remained. They detected radio noise corresponding...

The restrooms of the downtown Dortmund pub Kraftstoff (meaning “fuel”) are wallpapered with a superhero cartoon, in which the protagonist announces stone-faced: “I’m looking for a very rare key, made out of the finest crystal and hidden in a deep vault.” This picture is an ideal metaphor for neutrino physics in the new millennium. Neutrinos are indeed sought in the deep vaults of underground labs, and they indeed could serve as keys for GUT theories—or even more exotic theories—to explain the physics of elementary particles. The link between neutrino masses and the deepest mysteries of the particle world...

The San Francisco Bay Area is a magical place. Its Golden Gate Bridge (Fig. 12.1), a symbol in steel and an object of projection for dreams, stretches across the bay, sometimes—depending on the light—a lucent red. It’s an area that, over the years, has irresistibly attracted gold diggers, Beat poets, hippies, gays, computer nerds, oddballs, and creative people of all kinds—men and women who dreamed of a life outside of all social conventions where they could freely follow their ideas, impulses, and affections, and could try out whatever seemed attractive. New ideas and creativity are also the...

Actually, nobody has the faintest clue what time really is.

Why is time always running forward and never backward? Or in circles? Would backward-running time be possible at all? Is it possible to send messages, or even to travel, back in time? The reason physicists discuss the possibility of time travel at all can be traced back to the theory of general relativity.

The concept of a universal and ever-increasing time that is consistent for all observers came to a sudden end when, in 1905, a technical expert third class in a Swiss patent office used his spare time—and...

Nobody would have anticipated the present that Albert Einstein received for his seventieth birthday from his friend Kurt. Least of all probably Einstein himself. Kurt Gödel was an unimpressive, small man, then in his mid-forties, lonely and pessimistic, hypochondriac and neurotic—full of fear that he might be killed by jealous colleagues or poisoned by refrigerator emissions, believing in ghosts, and barely eating anything, apart from baby food.¹ In spite of their different personalities, Gödel had for quite a while been accompanying the cheerful Einstein on his extensive walks around Princeton (Fig. 14.1). And in doing so the two men,...

I had my first postdoc job in Nashville, Tennessee: Music City, USA. It is one of the fixed points of the Memphis–New Orleans–Nashville triangle, where almost everything that America spawned in blues, jazz, country, folk, and rock originated. If you turn on the radio in the South, almost every third song tells about one of these cities, the Mississippi River, the Tennessee River, the wide plains of Alabama, or the highways in between. Nashville is a prime destination for hopeful singers, songwriters, and bands of every kind, who play for tips in bars and restaurants and hope to...

Starting in the spring of 2010, the LHC—the largest machine ever built by mankind—produced particle collisions with 7 TeV center-of-mass energy, on its way to its design energy of 14 TeV (see Fig. 16.1). Just like the pioneers of the American west, we enter an unknown territory: a wilderness where we don’t know what to expect, but where we hope to encounter new exciting physics. The hierarchy problem and the need for dark matter in the universe provide a strong motivation for these hopes.

But is there any connection with neutrinos? There are actually good reasons for such...

When I was ten years old none of the boys in my class liked to dance. The only song that really drove all of us onto the dance floor was “Major Tom” by Peter Schilling. Somehow every one of us could identify with the sad story of the lonely astronaut, whose spaceship suddenly left its intended trajectory and—“drifting, falling, floating, weightless” (in the English version) or “totally detached” (as in the German original)—just like a modern Icarus, followed a mysterious light into the deathly realms of endless space. The last lines are “Now the light commands. This is...