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Investigating the utility of Real Quantum Mechanics (QM) and QM with a superselection rule (SSR) in describing experimental statistics. Real QM and SSR QM can potentially explain all experimental statistics. Understanding the conventional choices between Real vs. Complex QM and QM with vs. without SSR. Delve into the appropriateness of SSR in experimental situations and the role of reference frames in QM.
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Quantum Mechanics over the real field Robert Spekkens Department of Applied Mathematics and Theoretical Physics University of Cambridge July 24, 2007 FQXi Funding by: The Royal Society TexPoint fonts used in EMF. Read the TexPoint manual before you delete this box.: AAAAAA
Questions about the utility of Real QM: Might there be experimental situations where the statistics are well described by Real QM? Might it be that *all* experimental statistics can be explained using Real QM, and that the use of Real vs. Complex is a conventional choice of the physicist?
Questions about the utility of QM with a superselection rule: Might there be experimental situations where the statistics are well described by QM with a SSR? Might it be that *all* experimental statistics can be explained using QM with a SSR, and that the use of QM with vs. without SSR is a conventional choice of the physicist? YES YES
QM with a superselection rule Standard view: some conserved quantities are axiomatically superselected, others not SSR No SSR Charge Atom number univalence Linear momentum Angular momentum Photon number
QM with SSR is appropriate if one lacks a reference frame no RF W2SO(3) Unknown!
QM with SSR can describe *any* experiment External RF paradigm States Measurements Internal RF paradigm States Measurements and group invariant One can find a mapping such that
Define where with and See: Kitaev, Mayers and Preskill, Phys. Rev. 69, 052326 (2004) Bartlett, Rudolph and Spekkens, Rev. Mod. Phys. 79, 555 (2007)
QM with SSR can always be used if one wishes External RF paradigm States Measurements Internal RF paradigm States Measurements and group invariant Whether internal RF paradigm or external RF paradigm is used is a conventional choice of the physicist See: Aharonov and Susskind, Phys. Rev. 155, 1428 (1967) Bartlett, Rudolph and Spekkens, Int. J. Quantum Inf. 4, 17 (2006).
Can Real QM emerge by lacking some resource? Some resource Without resource Relative arrow of time unknown?
Can Real QM describe *any* experiment? External resource paradigm Some resource States Measurements Internal resource paradigm Some resource States Measurements and real Can one find a mapping such that
Define where
Can Real QM describe *any* experiment? External resource paradigm Some resource States Measurements Internal resource paradigm Some resource States Measurements and real If so, then whether external or internal paradigm is used is a conventional choice of the physicist i.e. no matter of fact about nature of field!