| 1. |
- Baek, I. H., et al.
(författare)
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Passive mode-locking of a Ti: Sapphire laser using low-dimensional carbon nanostructures
- 2011
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Ingår i: Int. Quantum Electron. Conf., IQEC Conf. Lasers Electro-Opt., CLEO Pac. Rim. Incorporating Australas. Conf. Opt., Lasers Spec. - 9780977565771 ; , s. 1154-1155
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Konferensbidrag (refereegranskat)abstract
- We report on passive mode-locking of a Ti:sapphire laser employing novel saturable absorbers based on low-dimensional carbon nanostructures such as single-walled carbon nanotubes and monolayer graphene. The mode-locked operation with both saturable absorbers were characterized and compared to pure Kerr-lens mode-locking.
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| 2. |
- Chen, P., et al.
(författare)
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Naked Black Hole Firewalls
- 2016
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Ingår i: Physical Review Letters. - : American Physical Society. - 0031-9007 .- 1079-7114. ; 116:16
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Tidskriftsartikel (refereegranskat)abstract
- In the firewall proposal, it is assumed that the firewall lies near the event horizon and should not be observable except by infalling observers, who are presumably terminated at the firewall. However, if the firewall is located near where the horizon would have been, based on the spacetime evolution up to that time, later quantum fluctuations of the Hawking emission rate can cause the "teleological" event horizon to have migrated to the inside of the firewall location, rendering the firewall naked. In principle, the firewall can be arbitrarily far outside the horizon. This casts doubt about the notion that firewalls are the "most conservative" solution to the information loss paradox.
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| 3. |
- Chen, P., et al.
(författare)
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Black hole remnants and the information loss paradox
- 2015
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Ingår i: Physics reports. - : Elsevier. - 0370-1573 .- 1873-6270. ; 603, s. 1-45
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Forskningsöversikt (refereegranskat)abstract
- Forty years after the discovery of Hawking radiation, its exact nature remains elusive. If Hawking radiation does not carry any information out from the ever shrinking black hole, it seems that unitarity is violated once the black hole completely evaporates. On the other hand, attempts to recover information via quantum entanglement lead to the firewall controversy. Amid the confusions, the possibility that black hole evaporation stops with a "remnant" has remained unpopular and is often dismissed due to some "undesired properties" of such an object. Nevertheless, as in any scientific debate, the pros and cons of any proposal must be carefully scrutinized. We fill in the void of the literature by providing a timely review of various types of black hole remnants, and provide some new thoughts regarding the challenges that black hole remnants face in the context of the information loss paradox and its latest incarnation, namely the firewall controversy. The importance of understanding the role of curvature singularity is also emphasized, after all there remains a possibility that the singularity cannot be cured even by quantum gravity. In this context a black hole remnant conveniently serves as a cosmic censor. We conclude that a remnant remains a possible end state of Hawking evaporation, and if it contains large interior geometry, may help to ameliorate the information loss paradox and the firewall controversy. We hope that this will raise some interests in the community to investigate remnants more critically but also more thoroughly.
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| 4. |
- Chen, P., et al.
(författare)
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Generalized uncertainty principle : Implications for black hole complementarity
- 2014
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Ingår i: Journal of High Energy Physics (JHEP). - 1126-6708 .- 1029-8479. ; 2014:12
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Tidskriftsartikel (refereegranskat)abstract
- At the heart of the black hole information loss paradox and the firewall controversy lies the conflict between quantum mechanics and general relativity. Much has been said about quantum corrections to general relativity, but much less in the opposite direction. It is therefore crucial to examine possible corrections to quantum mechanics due to gravity. Indeed, the Heisenberg Uncertainty Principle is one profound feature of quantum mechanics, which nevertheless may receive correction when gravitational effects become important. Such generalized uncertainty principle [GUP] has been motivated from not only quite general considerations of quantum mechanics and gravity, but also string theoretic arguments. We examine the role of GUP in the context of black hole complementarity. We find that while complementarity can be violated by large N rescaling if one assumes only the Heisenberg’s Uncertainty Principle, the application of GUP may save complementarity, but only if certain N -dependence is also assumed. This raises two important questions beyond the scope of this work, i.e., whether GUP really has the proposed form of N -dependence, and whether black hole complementarity is indeed correct.
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| 5. |
- Seger, Kai, et al.
(författare)
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Carbon nanotube mode-locked vertical external-cavity surface-emitting laser
- 2014
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Ingår i: Vertical External Cavity Surface Emitting Lasers (VECSELs) IV. - : SPIE - International Society for Optical Engineering. - 9780819498793 ; , s. 896606-
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Konferensbidrag (refereegranskat)abstract
- Mode-locking an optically pumped semiconductor disk laser has been demonstrated using low-loss saturable absorption containing a mixture of single-walled carbon nanotubes in PMM polymer. The modulator was fabricated by a simple spin-coating technique on fused silica substrate and was operating in transmission. Stable passive fundamental modelocking was obtained at a repetition rate of 613 MHz with a pulse length of 1.23 ps. The mode-locked semiconductor disk laser in a compact geometry delivered a maximum average output power of 136 mW at 1074 nm.
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