|Abstract||We pose and resolve a seeming paradox about spontaneous symmetry breaking in the quantum theory of infinite systems. For a symmetry to be spontaneously broken, it must not be implementable by a unitary operator. But Wigner's theorem guarantees that every symmetry is implemented by a unitary operator that preserves transition probabilities between pure states. We show how it is possible for a unitary operator of this sort to connect the folia of unitarily inequivalent representations. This result undermines interpretations of quantum theory that hold unitary equivalence to be necessary for physical equivalence.|
|Keywords||philosophy of physics quantum field theory|
|Categories||categorize this paper)|
|Through your library||Only published papers are available at libraries|
Similar books and articles
John Earman (2004). Curie's Principle and Spontaneous Symmetry Breaking. International Studies in the Philosophy of Science 18 (2 & 3):173 – 198.
Alexandre Laforgue (1993). Les Brisures de Symetrie du Temps. Acta Biotheoretica 41 (1-2).
Alexandre Laforgue (1994). Les Brisures de Symetrie du Temps. Acta Biotheoretica 42 (1).
Chuang Liu (2003). Classical Spontaneous Symmetry Breaking. Philosophy of Science 70 (5):1219-1232.
Doreen Fraser (2012). Spontaneous Symmetry Breaking: Quantum Statistical Mechanics Versus Quantum Field Theory. Philosophy of Science 79 (5):905-916.
Chuang Liu & Gerard G. Emch (2005). Explaining Quantum Spontaneous Symmetry Breaking. Studies in History and Philosophy of Science Part B 36 (1):137-163.
Steven French (2012). Unitary Inequivalence as a Problem for Structural Realism. Studies in History and Philosophy of Science Part B 43 (2):121-136.
Laura Ruetsche (2003). A Matter of Degree: Putting Unitary Inequivalence to Work. Philosophy of Science 70 (5):1329-1342.
David John Baker (2013). Identity, Superselection Theory, and the Statistical Properties of Quantum Fields. Philosophy of Science 80 (2).
David Baker (2011). Broken Symmetry and Spacetime. Philosophy of Science 78 (1):128-148.
Added to index2011-03-21
Total downloads106 ( #6,971 of 722,933 )
Recent downloads (6 months)49 ( #1,215 of 722,933 )
How can I increase my downloads?