Online research in philosophy

Alternate View Column AV-02 Keywords: cosmology, bubble, universe, inflation Published in the September-1984 issue of Analog Science Fiction & Fact Magazine; This column was written and submitted 2/10/84 and is copyrighted ©1984, John G. Cramer. All rights reserved. No part may be reproduced in any form without the explicit permission of the author.

Alternate View Column AV-62 Keywords: quantum nonlocality entangled states recreation communication Published in the December-1993 issue of Analog Science Fiction & Fact Magazine ; This column was written and submitted 5/17/93 and is copyrighted ©1993 by John G. Cramer. All rights reserved. No part may be reproduced in any form without the explicit permission of the author.

When matter is falling into a black hole, the associated information becomes unavailable to the black hole's exterior. If the black hole disappears by Hawking evaporation, the information seems to be lost in the singularity, leading to Hawking's information paradox: the unitary evolution seems to be broken, because a pure separate quantum state can evolve into a mixed one.



This article proposes a new interpretation of the black hole singularities, which restores the information conservation. For the Schwarzschild black hole, it presents new coordinates, which move the singularity at the future infinity (although it can still be reached in finite proper time). For the evaporating black holes, this article shows that we can still cure the apparently destructive effects of the singularity on the information conservation. For this, we propose to allow the metric to be degenerate at some points, and use the singular semiriemannian geometry. This view, which results naturally from the Cauchy problem, repairs the incomplete geodesics.



The reinterpretation of singularities suggested here allows (in the context of standard General Relativity) the information conservation and unitary evolution to be restored, both for eternal and for evaporating black holes.

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When matter is falling into a black hole, the associated information becomes unavailable to the black hole's exterior. If the black hole disappears by Hawking evaporation, the information seems to be lost in the singularity, leading to Hawking's information paradox: the unitary evolution seems to be broken, because a pure separate quantum state can evolve into a mixed one.



This article proposes a new interpretation of the black hole singularities, which restores the information conservation. For the Schwarzschild black hole, it presents new coordinates, which move the singularity at the future infinity (although it can still be reached in finite proper time). For the evaporating black holes, this article shows that we can still cure the apparently destructive effects of the singularity on the information conservation. For this, we propose to allow the metric to be degenerate at some points, and use the singular semiriemannian geometry. This view, which results naturally from Ashtekar's new variables formulation of Einstein's equation, repairs the incomplete geodesics.



The reinterpretation of singularities suggested here allows (in the context of standard General Relativity) the information conservation and unitary evolution to be restored, both for eternal and for evaporating black holes.

Alternate View Column AV-58 Keywords: Japan science fiction HamaCon physics Tscuba KEK TRISTAN Published in the April-1993 issue of Analog Science Fiction & Fact Magazine ; This column was written and submitted 9/17/92 and is copyrighted ©1992 by John G. Cramer. All rights reserved. No part may be reproduced in any form without prior explicit permission of the author.

Alternate View Column AV-38 Keywords: special relativity, twin paradox, time dilation, starship, Einstein, Lorentz factor Published in the March-1990 issue of Analog Science Fiction & Fact Magazine; This column was written and submitted 8/20/89 and is copyrighted © 1989, John G. Cramer. All rights reserved. No part may be reproduced in any form without the explicit permission of the author.

Alternate View Column AV-69 Keywords: NASA Workshop relativity quantum mechanics wormholes FTL Published in the Mid-December-1994 issue of Analog Science Fiction & Fact Magazine ; This column was written and submitted 5/22/94 and is copyrighted ©1994 by John G. Cramer. All rights reserved. No part may be reproduced in any form without the explicit permission of the author.

Alternate View Column AV-81 Keywords: Alcubierre Warp Drive FTL spacewarp solution Einstein's equations general relativity Published in the November-1996 issue of Analog Science Fiction & Fact Magazine ; This column was written and submitted 4/15/96 and is copyrighted ©1996 by John G. Cramer. All rights reserved. No part may be reproduced in any form without the explicit permission of the author.

This Alternate View column marks three milestones: This is the 3rd anniversary of my start as an AV columnist for Analog, this is the 20th AV column I've written, and it is also the 7th anniversary of my first publication in Analog. I enjoy writing these columns on scientific subjects, but it can be frustrating. Science is continually changing as new experimental results and observations are made, as new ideas and theories are conceived and old ideas are rejected. Often by the time an Alternate View column on some new development in physics or astronomy appears in these pages the field has already progressed further and there is more to be said. So this third anniversary column will be used as an occasion for a backward look at some of the subjects covered in previous columns and articles, giving an update on more recent developments. An index of my first 20 AV columns and articles is provided below. This can be used as a reference guide to indicate which topics were discussed in which columns and articles.

This column is a milestone. In 1983, while I was on a one year sabbatical at the Hahn Meitner Institute for Nuclear Physics in what was then West Berlin, I received a letter from Stan Schmidt informing me that Jerry Pournelle had decided that he no longer wished to be an Alternate View columnist for Analog and asking if I was interested in taking over as the AV columnist and “alternating” with G. Harry Stine.