The Thought Experiment
The Wigner's Friend thought experiment posits a friend of Wigner who performs the Schrödinger's cat experiment after Wigner leaves the laboratory. Only when he returns does Wigner learn the result of the experiment from his friend, that is, whether the cat is alive or dead. The question is raised: was the state of the system a superposition of "dead cat/sad friend" and "live cat/happy friend," only determined when Wigner learned the result of the experiment, or was it determined at some previous point?
Read more about this topic: Wigner's Friend
Famous quotes containing the words thought and/or experiment:
“He asked if I would sell my Christmas trees;
My woods the young fir balsams like a place
Where houses all are churches and have spires.
I hadn’t thought of them as Christmas trees.”
—Robert Frost (1874–1963)
“It is proper to take alarm at the first experiment on our liberties.... Who does not see that the same authority which can establish Christianity, in exclusion of all other Religions, may establish with the same ease any particular sect of Christians, in exclusion of all other sects?”
—James Madison (1751–1836)