Imperial College London
Alternate

Prof Joao Magueijo

Faculty of Natural Sciences, Department of Physics

Professor of Physics
 
 
 
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Contact

 

j.magueijo Website

 
 
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Location

 

Huxley BuildingSouth Kensington Campus

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Summary

 

Publications

Citation

BibTex format

@article{Barrow:2021:10.1007/s10701-021-00433-0,
author = {Barrow, JD and Magueijo, J},
doi = {10.1007/s10701-021-00433-0},
journal = {Foundations of Physics: an international journal devoted to the conceptual and fundamental theories of modern physics, biophysics, and cosmology},
title = {A contextual Planck parameter and the classical limit in quantum cosmology},
url = {http://dx.doi.org/10.1007/s10701-021-00433-0},
volume = {51},
year = {2021}
}
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RIS format (EndNote, RefMan)

TY  - JOUR
AB  - We propose that whatever quantity controls the Heisenberg uncertainty relations (for a given complementary pair of observables) it should be identified with an effective Planck parameter. With this definition it is not difficult to find examples where the Planck parameter depends on the region under study, varies in time, and even depends on which pair of observables one focuses on. In quantum cosmology the effective Planck parameter depends on the size of the comoving region under study, and so depends on that chosen region and on time. With this criterion, the classical limit is expected, not for regions larger than the Planck length, lP, but for those larger than lQ=(l2PH−1)1/3, where H is the Hubble parameter. In theories where the cosmological constant is dynamical, it is possible for the latter to remain quantum even in contexts where everything else is deemed classical. These results are derived from standard quantization methods, but we also include more speculative cases where ad hoc Planck parameters scale differently with the length scale under observation. Even more speculatively, we examine the possibility that similar complementary concepts affect thermodynamical variables, such as the temperature and the entropy of a black hole.
AU  - Barrow,JD
AU  - Magueijo,J
DO  - 10.1007/s10701-021-00433-0
PY  - 2021///
SN  - 0015-9018
TI  - A contextual Planck parameter and the classical limit in quantum cosmology
T2  - Foundations of Physics: an international journal devoted to the conceptual and fundamental theories of modern physics, biophysics, and cosmology
UR  - http://dx.doi.org/10.1007/s10701-021-00433-0
UR  - http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcApp=PARTNER_APP&SrcAuth=LinksAMR&KeyUT=WOS:000620647500001&DestLinkType=FullRecord&DestApp=ALL_WOS&UsrCustomerID=1ba7043ffcc86c417c072aa74d649202
UR  - http://hdl.handle.net/10044/1/101367
VL  - 51
ER  -
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