Its equations describe multiple possible outcomes for a measurement in the subatomic realm. Physicists have devised a dozen or two different interpretations of what that really means. And in turn, dozens and dozens of books have been written to explain, defend or deny the validity of those various interpretations.
Caltech physicist Sean Carroll’s Something Deeply Hidden defends one of the most provocative of those interpretations: that multiple possible measurement outcomes imply a multiplicity of universes. Known as the Many-Worlds Interpretation, that view contends that all the possible outcomes of quantum experiments actually come true.
Measuring the spin of an electron, for instance, might yield the result that the spin axis points either up or down. When the measurement is made, the universe splits, branching into two copies, one with the spin up, the other with the spin down. As each measurement is made, this view of quantum theory insists, additional universes are instantly created.
“The theory describes many copies of what we think of as ‘the universe,’ ” Carroll writes, “each slightly different, but each truly real in some sense.” If you want to know where these branches are, he says, “There is no ‘place’ where those branches are hiding; they simply exist simultaneously, along with our own, effectively out of contact with it.”
Many Worlds is a well-known quantum interpretation, originated in the 1950s by American physicist Hugh Everett III. It was mostly ignored for a long time. But in recent decades, many physicists have found it (or variants of it) preferable to the traditional view of quantum mechanics associated with Danish physicist Niels Bohr.
Caltech physicist Sean Carroll’s Something Deeply Hidden defends one of the most provocative of those interpretations: that multiple possible measurement outcomes imply a multiplicity of universes. Known as the Many-Worlds Interpretation, that view contends that all the possible outcomes of quantum experiments actually come true.
Measuring the spin of an electron, for instance, might yield the result that the spin axis points either up or down. When the measurement is made, the universe splits, branching into two copies, one with the spin up, the other with the spin down. As each measurement is made, this view of quantum theory insists, additional universes are instantly created.
“The theory describes many copies of what we think of as ‘the universe,’ ” Carroll writes, “each slightly different, but each truly real in some sense.” If you want to know where these branches are, he says, “There is no ‘place’ where those branches are hiding; they simply exist simultaneously, along with our own, effectively out of contact with it.”
Many Worlds is a well-known quantum interpretation, originated in the 1950s by American physicist Hugh Everett III. It was mostly ignored for a long time. But in recent decades, many physicists have found it (or variants of it) preferable to the traditional view of quantum mechanics associated with Danish physicist Niels Bohr.
