Learning curve: Sanaa's spectacular floating Lausanne library rockets them into architecture's premier league

In Lausanne yesterday, the feted Japanese architects Kazuo Sejima and Ryue Nishizawa – aka Sanaa – became the profession's anointed artists of the floating world. Their new SF110m (£65m) building is a fluid exercise in glass and concrete. It is called the Rolex Learning Centre. Yet visually, it is the reverse – a kind of unlearning centre where the doors of perception melt into a soft vitreous glaze and shape and edge become ambiguous.

If you enjoyed the refined delights of Sanaa's 2009 Serpentine Pavilion, you will have no trouble recognising the conceptual genetics of the Rolex Learning Centre: the pavilion was the skeleton of this much bigger idea. And here it is, on the campus of the Ecole Polytechnique Fédérale de Lausanne, where the scientific research is as highly rated as that of Cambridge or Imperial College.

Scientists require chains of repeatable causes and effects. In Sanaa's building one experiences effects; the causes seem secondary. Ah, so this must be shock-of-the-new architecture! No, it isn't. And here's the proof: "Today's artist lives in an era of dissolution without guidance. The old forms are in ruins, the benumbed world is shaken up, the old human spirit is invalidated and in flux towards a new form. We float in space, and cannot perceive the new order."

That quote – and I'm typing this, very aptly, at a desk on a plateau floating above the library in the Centre – is from Walter Gropius, the godfather of modernist architecture, and he said it in 1919 in Berlin. Nothing is ever quite new in architecture, it just gets more sophisticated in terms of materials and details. Sanaa are simply the politely creative grandchildren of Gropius; and the grandchildren of the Swedish genius Alvar Aalto too. Aalto's Paradise Restaurant at the 1930 Stockholm Exhibition was one of the first buildings to use glass as a kind of skin.

The penny drops. The Rolex Learning Centre, with its swerves and blurs of glass, is more like a weirdly stretched and twisted version of Aalto's Savoy vase. Or Oscar Niemeyer's fabulously sexy Brazilian architecture on acid. But this building is not an object or a jolly hallucination. It is a library, an experimental place of learning. Sanaa and the university are trying something new. They call the building a landscape for learning. Alpine metaphors queue up: ski slopes, luge and slalom runs, hillsides. The key word is not "architecture", it is "topography".

The architects explain the idea succinctly: "Inside, the hills, valleys and plateaus formed by the undulations often make the edges of the building invisible, though there are no visual barriers between one area and the next. Instead of steps and staircases, there are gentle slopes and terraces. Clearly, but without dividing walls, one area of activity gives way to another."

And that's the big idea, in one sentence. Without quite knowing how, one passes from bookstacks to cafés and from cafés to courtyards. There are no dividing walls – even of glass – between one area of activity and another. The only thing the glass does is sheath the external walls as they dip and rise around the 88,000 cubed metres site, clothing the 14 voids that punch down through the undulating concrete souffle.

There is no fixed vista. Move your eyes only slightly and the view changes greatly. And it is a view composed of layers of transparency and overlaps of physical content. In use, and filled with students, this will be a university building for the Facebook generation – a place where intellectual and purely visual information will be on equal footing.

The Rolex Learning Centre is therefore meant to be a chilled sort of place. Yet architecturally, the dominating effect is not quite of a relaxed form but of an out-and-out display of design virtuosity. The exterior concrete formwork is so superior that it has a polished sheen, even though it has not been polished; the glazing is precisely detailed; the complex geometry of the rise and falls of the internal landscape is so well done that it is hard to see any points of transition.

Yet it is what you can't see – the structure holding up this internal landscape – that is probably the most original thing about the building. The forming of the concrete had to be extraordinarily precise because the rise and fall of the glass façades has to handle slight movements. The laser-cut formwork was positioned using GPS technology; the structure is made up of two concrete shells and between them are 11 arches, anchored to 70 underground cables. This is real gee-whizz stuff that makes architecture look effortless.

Sanaa's architecture here may represent a new experiment in educational environments, but it is also quite obviously a straightforward refinement of a design riff that they have been quietly perfecting since their 21st Century Museum in Japan in 2004 announced them as incipient masters of glass architecture. The museum is a circular glazed building containing square glass pavilions. Two years later, Sanaa's Glass Pavilion in Toledo, Ohio, was the opposite: a square form containing 32,000 square feet of Austrian glass in rounded pavilions, some flowing past others.

The Rolex Learning Centre is this game of glass taken to another level – or series of levels. For Sanaa, the building is of huge significance. It confirms them as the 21st century's leaders in the creation of transparent architecture and they have risen without so much as a squeak – no polemics or manifesto, no desire to be thought of as charismatic. They simply pursue the design of buildings that look ethereal but are actually very highly wrought in terms of form and concrete technology.

And so, with the Rolex Learning Centre and their forthcoming Louvre annexe at Lens, they join the premier league. In the major cultural architecture stakes, Renzo Piano, Zaha Hadid, Frank Gehry and Steven Holl have serious competition. And if there was any doubt about the extent of Sanaa's ascent, they have been commissioned to design a new distribution centre at that holy of holies, the Vitra Design Museum at Weil-am-Rein in Germany.

That may give some comfort and a sense of kudos to students who use the Learning Centre's admirable cache of architectural source material. As will cutting-edge active information systems that can tell them the noise levels in different parts of the building.

Is this great architecture? The Rolex Learning Centre is certainly no advance on the architectural vision of Walter Gropius in 1919. And yet the building may, by chance, be the perfect metaphor for something quite riveting going on elsewhere on the EPFL campus.

Supported by a supercomputer called Blue Brain, researchers are building virtual maps of how neurons, which carry messages through the brain and spinal chord, actually behave. Blue Brain's maps are edging us closer to an understanding of the way memories and dreams form, and how our thinking processes work at an electro-chemical level.

"This has important cognitive potential," said a university spokesman, Jérôme Gross. "It could lead to neuro-prosthetics – future vision devices." Sitting here, engulfed in this swirling architecture, the phrase "future vision devices" seems to sum up Sanaa's building better than the usual vocabulary of architectural discourse.

Top of the class: Architecture for academics

Simmons Hall, MIT, Cambridge, Maryland/ Steven Holl: Steven Holl, now the most sought-after American architect, produced this extraordinary 350-bed dormitory, dining hall and auditorium. The building is highly porous: it has five large openings, big light-wells and each bedroom has nine openable windows

Shipping & Transport College, Rotterdam/ Neutelings Riedijk: A classic design in the late-1990s Rotterdam Super Dutch manner – Peckham Library on steroids. The dramatic cantilevered form emerged in the Cloud-Iron building proposed by El Lissitzky, the legendary 1920s Russian Suprematist artist

Richard B. Fisher Centre for Performing Arts, Bard College, New York state/Frank Gehry: This flailing form is like a wild yell shattering a sylvan setting. The drama of the building's outer envelope becomes more familiar internally, a home for dance, theatre, jazz and opera

Peter Aaron

M Beinecke Rare Book and Manuscript Library, Yale/ Skidmore, Owings & Merrill: SOM's Gordon Bunshaft said there was nothing to it – just a bookstack, heating and humidity controls, reading rooms "and some exhibition space for little books and stuff". In fact, it contains nearly 800,000 rare books and manuscripts. One critic called the grey marble exterior 'a stack of television sets'