Saturday, June 28, 2014

Quantum Yoga

Cambridge, MA (June 18, 2005)

The main thing with Cambridge, Massachusetts, is its diversity. The big universities are the focus of a vibrant multi-ethnic community, with Harvard Square and Central Square its centers of gravity. The two squares are a joy to visit, as they host many small bookstores (revolution books yay!) and restaurants, still somehow able to survive despite the gentrification that followed the housing bubble. Among our favorite places in Harvard Square, however, there is a very special yoga studio

The studio is special because of its owner, Jesse. We started frequenting him when the studio was at its infancy, in a small basement room in Harvard Square just big enough for a few mats along one wall (I once managed to actually dent the wall, which tells a lot about my "flexibility"). Now the studio has grown a lot, opened a second downtown location, a "donation" studio (you pay what you can) a no-kill animal shelter, and much more. But Jesse is still the same Jesse, and we were lucky of being able to meet him for a chat during our last Boston visit. And as usual with Jesse, we talked about science and the nature of reality as described by physics (Jesse is more up to date about science news than me).

Riverfest in Cambridge
All this came back to my mind a couple of days ago as I read a few articles celebrating the 50 years since the publication of the Bell's Theorem, that more than any other results in modern physics is at the base of our attempts to understand reality. The theorem applies to quantum mechanics, the foundational theory of modern physics. Developed at the beginning of the XX century, quantum mechanics describes the behaviour of subatomic particles and forces. It replaces the determinisms of classical mechanics (where everything is predictable with clockwork precision) with a probabilistic approach. With quantum mechanics you cannot foretell where a particle will be at a given time, only estimate the probability that it will be there, or at any other location. This view, which is based on the work of Niels Bohr and the "Copenhagen" school, has been found to be inherently unsatisfactory to many scientists, including Albert Einstein when he proclaimed that "God doesn't play dice with the world". The favorite loophole invoked by the critics was to assume that quantum mechanics was an incomplete theory, e.g. that there was some missing equation with hidden variables that, if measured, would predict the exact outcome of any physics experiment. Bell's theorem closed this loophole, by showing that any physical theory (including quantum mechanics) cannot have hidden local variables. As a consequence, the world is either inherently random (and the exact result of any experiment is unknowable until somebody measures its outcome), or physics is non-local.

Losing locality, however, is as bad for common sense as much as believing in a random universe. If physics is non-local then anything anywhere in the universe can in principle affect, instantaneously, the outcome of a physics experiment. This contradiction was famously popularized by Einstein, again, when he suggested that the loss of locality would lead to a "spooky action at a distance", where entangled particles would have the mysterious ability to determine each other status instantaneously as if they could communicate "telepathically". While this paradox was proposed to show the absurdity of a non-local universe, reality is full of surprises, and quantum entanglement (as this spooky action at a distance is called) was indeed confirmed in several experiment starting from 1972. The story of how these experiments is interesting in itself, and beautifully narrated in the book "How The Hippies Saved Physics". This the story of a band of physicists coming from the counterculture of the fabulous sixties set out to understand the deeper meaning of physics in between acid trips and paranormal experiments. While they did not prove the existence of telepathy and the new age idea of the oneness of the universe, they did demonstrate the reality of quantum entanglement, inventing in the process the field of quantum encryption and quantum computing.

While quantum entanglement seems to suggest that physics is indeed not local, superluminal communication is still prohibited by Einstein special relativity. The true meaning of this spooky action at a distance, as a consequence, is quite obscure. Living in a fundamentally unpredictable universe is however also very unsatisfactory, despite the sci-fi appeal of multi world theories where all possible quantum solutions do happens at the same time, just in different "parallel" universes. A century after being discovered, we casually use quantum mechanics without even noticing, every time we turn on the switch of any electronic devices whose semiconductor technology is based on the weird nature of quantum mechanics. Yet, like children playing with magic toys from alien civilizations, we are still far from understanding the deep principles upon which our gadgets are based and, fifty years after the publication of Bell's theorem, the true nature of our quantum universe.

Boston seen from Cambridge, MA (June 18, 2005)

Sunday, June 22, 2014

Two Schools in Newe Towne

Weeks Footbridge, Cambridge, MA (June 18, 2005)

When I say that I lived in Boston for 12 years, I really mean Cambridge, MA. Cambridge, on the other side of the Charles river, is the left-wing, intellectual counterpart to the financial centers / 1 percenter character of downtown Boston. Hosting both Harvard and MIT, even its name is a tribute to its ivory-tower destiny. When in 1636 the legislature of Massachusetts Bay Colony voted to form a College for training its Puritan ministers, the school that would later become Harvard University was established in the village of Newe Towne. In less than two years, as the College was becoming more and more successful, the name of the village was changed to Cambridge, in honour to the renowned England university. That sealed the fate for the little village across the Charles river, destined to become a beacon of culture and power that century later would rival its namesake across the pond.

Fountain across the Harvard Yard, in Cambridge
The center of Cambridge is Harvard Square, the original location of Newe Towne, and the current site of the Harvard Yard. That's where you find the red-brick-ivy-covered buildings one typically associates to an ivy-league University. They are still there, the old dorms where the freshmen stay when they arrive to the College, to be inoculated with the germs that will make them true-crimson pureblood harvardians for the rest of their life. Even today, Harvard is the university most associated with the US ruling class, a class of lawyers and graduates from its famous school of Government dedicated to John F. Kennedy, J.F.K. Despite being established by the legislature of the Colony, Harvard is now a private University. A huge one, with an endowment so large (over 30 billion dollars) that if it wants, Harvard could offer free education to all its students.

Then there is the MIT. Closer to the river, the Massachusetts Institute of Technology was established two days before the start of the civil war when the country realized that the development of science and technology was essential for its future (oh, how would you wish this is still true). It was modeled after the tradition of the european polytechnic schools. It is now one of the most selective universities in the world, with less than 8% acceptance rate. Many of the technological inventions that define our age have originated in halls of the MIT, whose symbol is the large dome visible across the river in the photo at the bottom. Strangely enough, the main rivalry of MIT students is not with Harvard, but rather with the California Institute of Technology, the Caltech in Pasadena, California. The story of the pranks between the two schools is legendary, and includes a real spanish cannon stolen from the Caltech campus and transported cross country to the MIT. This is just one of the many hacks for which the MIT students are famous.

The MIT dome, Cambridge, MA (September 6, 2008)

Wednesday, June 18, 2014

Like in the Movies

Boston, MA (September 6, 2008)

The first time I landed in the US was at the end of October. I came to visit Mayli, just a few months after she had moved to this country for graduate school, in one of the many Universities of Boston. At the time she was living in a small apartment in Somerville, one stop before the end of the red line.

Old State House
I still remember Mayli's letter describing her first landing at the Boston Logan International airport. How the city seemed impossibly large, extending in all directions not occupied by the ocean. But while she first landed in August, my first landing was in the fall: it was already after sunset and all I could perceive from my seat was the dark expanse of the Boston Bay and the sudden noise of the plane wheels hitting the tarmac. My first landing was not very scenic. Immigration: check (Italians at the time could get in the US for three months with just a passport stamp on entry; now they need to get a visa in advance). Custom: check (what could I possibly have to declare, in my rigid-frame suitcase with three weeks of underwear change?). Butterflies in the stomach (the anticipation of seeing Mayli). Actually finding her on the other side of terminal E's sliding doors. The taxi ride through the Sumner tunnel (for many years I thought is was dedicated to a season), negotiating the pre-Big Dig traffic all the way to Somerville. The small annex apartment in Clyde St. (tiny, but hey, not many graduate students were lucky enough to rent their own apartment).

That's how it began. 

Somerville didn't conform to my idea of the USA. My knowledge of american middle class neighborhoods came from the Milwaukee of Happy Days, but somehow I was expecting either the New York city of Annie Hall, or the desolation of the Bronx in a old Paul Newman cop movie. At least I knew I wasn't visiting the Old West, so I wasn't expecting horses and crazy tumbleweed bushes roaming in the desert. Somerville seemed a safe neighborhood, with its old and slightly run-down New England-style cardboard houses (I discovered that they were made of cardboard the first time I sat on the futon, when leaning back I heard the deaf sound of the wall as I hit it with my knuckles): it was no Bronx here. But the half-rusted cars parked along the cheap chain link fences, and the open-air tangle of wires hanging from the street wooden poles, not one of them standing straight, didn't have the glamour of Manhattan either. Reality was a little more prosaic than the Hollywood fiction. Yet all was so alien to me that even the chocolate chip cookies with earl grey tea in the humid and cold mornings tasted like the new world.

It rained a lot. Between the unpleasant rain and my exceedingly bad english I didn't dare to get out much alone the first days. When Mayli was busy, I spent most of my first week studying in the Tufts library, and watching the cat-sized squirrels in the extraordinarily green lawn across the library windows. Then the weekend finally came, and with it my real introduction to Boston. We took the T from Porter to Park Street, and from there we followed the freedom trail. I don't have photos taken in that expedition, but I remember it like the small image above on the left: wet pavement in front of tall modern buildings, and the occasional old-brick piece of history embedded in the glamour of a modern US city. We walked the full day, me still trying to reconcile the reality I was seeing with the idealized world remembered from TV. Then sunset arrived, with it the night's shadows enshrouding the urban landscape, now lit by the streetlamps and the car's headlights. That's when I saw it.

The steam rising from the manholes in the street. Like in the movies: at last, I found my America. 

Boston, MA (September 6, 2008)

Sunday, June 15, 2014

A Trip to Boston

Boston, MA (June 7, 2014)

The Summer Meeting of the American Astronomical Society, this year, was in Boston, Massachusetts. This was the perfect opportunity for me to return to the city where I lived for 12 years, before moving all the way to the middle of the country. The meeting was at the Westin Hotel in Copley, which is close to the Hancock tower, the tall blue building in photo above, right at the center of the city.

Sara Seager in Plenary
Summer AAS meetings tend to be smaller than the January meetings, yet there were almost 1,200 astronomers in town. The format of the meeting is the usual for the AAS: a number of plenary sessions spread through the day with parallel sessions in-between, where shorter talks were grouped thematically and delivered in smaller rooms. Two of my students were giving talks in the parallel sessions: one about his search of brown dwarf companions hiding in the periphery of extrasolar planetary systems, and the other about measuring the efficiency of star formation across the Galaxy. While the parallel session talks are delivered as brief "science" updates and tend to be very technical, the plenary talks are intended for a general astronomy audience, and tend to provide a broad overview of the field for non specialists. They are fun to attend. The picture on the left shows Sara Seager, extrasolar planets superstar from MIT, talking about the characterization of planetary systems found by the Kepler telescope, and the perspectives offered by future missions. Very timely, as the continuation of Kepler itself (the K2 mission) has just been approved by NASA (albeit at the expenses of other, equally useful, space telescopes). K2 is a cool hack: Kepler was designed to work with three reactions wheels, gyroscope-like devices that allow the precise pointing necessary to achieve its legendary photometric accuracy. Down to two wheels after malfunctions, Kepler was due to be retired until clever engineers figured that they could use the solar radiation with the remaining reaction wheels as a stabilizing force, the same way a sailboat use head-wind to coast against the current. Devilishly smart: it is rocket science after all. The K2 mission will operate differently than before, and its focus will be more on the stars hosting planets, rather than finding more planets like Earth: this is however as important as the search for extrasolar planetary systems, as pointed out by my Iowa State colleague Steve Kawaler in his excellent and entertaining plenary talk.

The meeting finished on Thursday, so I spent the last day of the week visiting the Harvard-Smithsonian Center for Astrophysics (CfA), which was my workplace for the 12 years I lived in Boston. It was nice to see everybody, including the part of my group that is in California (also in Boston for the meeting), and one of my graduate students there with a fellowship to finish her thesis. As a plus, I discovered that some of my CfA friends, including my old boss, had been converted into manga characters, as a part of a collaboration between US institutions and the Tohoku University in Sendai. How cool is that?

Fenway Park
I will talk more, in future posts, about the plenary talks at the AAS and my CfA visit. Let me finish this long overdue entry with a comment about the photos. As you have certainly noticed these are cameraphone photos, shot with my iPhone 5s, and processed in-phone with Snapseed. I didn't bring my "real" camera (the Nikon 700) with me, as I often do in trips that are mainly work. This trip was actually borderline, as I stayed in town for the weekend after the meeting, and went around shooting along the Charles river (top and bottom photo) and in the neighborhood of the hotel (which was just behind Fenway Park, the famed and sacred home field of the Boston Red Sox, photo on the right). But I have already amassed a quite large selection of Boston quality photos in the years I have lived there, so it was fun just walking around happily snapping snapshots with a phone, layering artsy textures in accordance to the mood I felt while I was pressing the shutter. After 5 years in the corn fields, one forgets the diversity of life in the large human conglomerates of the East coast cities. I have been frequently to Chicago, but it is different. One ends up living in the suburbs, and the suburbs of Chicago are not different than the suburbs of a midwestern university town. Boston (and Cambridge where I worked), had a unique pulse, which is difficult to replicate in the middle of the country. Or maybe I am just getting nostalgic?

Boston, MA (June 7, 2014)