ClashoftheQuantumTitans文献.doc

Clash of the Quantum Titans After decades of debate, disputes over the mathematical rules governing reality remain unresolved By Tom Siegfried November 20th, 2010; Vol.178 #11 (p. 15) Text Size Enlarge Zombie CatIn 1935, Austrian physicist Erwin Schr?dinger developed a cat-killing thought experiment to illustrate his annoyance with one of the oddest features of quantum mechanics...Read moreMichael Morgenstern Schr?dinger’s cat was born 75 years ago. Its date of death remains uncertain. Science’s most famous feline remains perpetually both alive and dead, a mythological zombie symbolizing an enduring enigma at the heart of modern physics. It’s an imaginary cat, of course, invented by Austrian physicist Erwin Schr?dinger in 1935 to emphasize the weirdness of quantum mechanics, the mathematical constitution governing the microworld. An experiment could be devised, Schr?dinger showed, to put a cat in a box into a live-dead limbo (technically, a “superposition” of states) until somebody looked inside. In the same paper, Schr?dinger described another quantum conundrum, known as entanglement, in which measuring one particle seemed to affect the properties of another a great distance away. Entanglement was the feature of quantum physics that Einstein lamented as “spooky action at a distance.” Semighostly cats and spooky long-distance influences both reflected the radical new view of reality that quantum theory imposed on 20th century physics. Quantum reality is ruled by probabilities. Instead of the rock-solid cause-and-effect world of Newtonian physics, humans occupy a casino universe with an undetermined future, a state of affairs that evoked Einstein’s famous complaint that God does not play dice. Although both Einstein and Schr?dinger helped give birth to quantum physics, they believed something was seriously amiss about it. Yet its predictions have always come true, no matter how absurd. Experiments have confirmed the Schr?dinger-cat superposition, for instance, wi