| Records |
Author  |
Armaza, C.; Hojman, S.A.; Koch, B.; Zalaquett, N. |
| Title |
On the possibility of non-geodesic motion of massless spinning tops |
Type |
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| Year |
2016 |
Publication |
Classical And Quantum Gravity |
Abbreviated Journal |
Class. Quantum Gravity |
| Volume |
33 |
Issue |
14 |
Pages |
18 pp |
| Keywords |
trajectory; massless; spin; curved spacetime |
| Abstract |
The motion of spinning massless particles in gravitationally curved backgrounds is revisited by considering new types of constraints. Those constraints guarantee zero mass (P μP μ= 0) and they allow for the possibility of trajectories which are not simply null geodesics. To exemplify this previously unknown possibility, the equations of motion are solved for radial motion in Schwarzschild background. It is found that the particle experiences a spin-induced energy shift, which is proportional to the Hawking temperature of the black hole background. |
| Address |
[Armaza, Cristobal; Koch, Benjamin; Zalaquett, Nicolas] Pontificia Univ Catolica Chile, Inst Fis, Av Vicuna Mackenna 4860, Santiago 7820436, Chile, Email: nzalaquett@gmail.com |
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| Publisher |
Iop Publishing Ltd |
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English |
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| ISSN |
0264-9381 |
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| Notes |
WOS:000378895900012 |
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| Call Number |
UAI @ eduardo.moreno @ |
Serial |
636 |
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| Author |
Asenjo, F.A.; Hojman, S.A. |
| Title |
Reply to Comment on 'Do electromagnetic waves always propagate along null geodesics?' Reply |
Type |
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| Year |
2021 |
Publication |
Classical And Quantum Gravity |
Abbreviated Journal |
Class. Quantum Gravity |
| Volume |
38 |
Issue |
23 |
Pages |
238002 |
| Keywords |
couplings; electromagnetic wave; propagation; consistency; geometrical; eikonal limit |
| Abstract |
A reply to the previous article commenting on non-geodesical propagation of electromagnetic fields on gravitational backgrounds and the eikonal limit are presented. |
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| ISSN |
0264-9381 |
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| Notes |
WOS:000728942300001 |
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| Call Number |
UAI @ alexi.delcanto @ |
Serial |
1512 |
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| Author |
Asenjo, F.A.; Hojman, S.A. |
| Title |
Do electromagnetic waves always propagate along null geodesics? |
Type |
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| Year |
2017 |
Publication |
Classical And Quantum Gravity |
Abbreviated Journal |
Class. Quantum Gravity |
| Volume |
34 |
Issue |
20 |
Pages |
12 pp |
| Keywords |
electromagnetic waves; curved spacetime; non-null geodesics |
| Abstract |
We find exact solutions to Maxwell equations written in terms of fourvector potentials in non-rotating, as well as in Gdel and Kerr spacetimes. We show that Maxwell equations can be reduced to two uncoupled secondorder differential equations for combinations of the components of the four-vector potential. Exact electromagnetic waves solutions are written on given gravitational field backgrounds where they evolve. We find that in non-rotating spherical symmetric spacetimes, electromagnetic waves travel along null geodesics. However, electromagnetic waves on Gdel and Kerr spacetimes do not exhibit that behavior. |
| Address |
[Asenjo, Felipe A.] Univ Adolfo Ibanez, Fac Ingn & Ciencias, Santiago, Chile, Email: felipe.asenjo@uai.cl; |
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| Publisher |
Iop Publishing Ltd |
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English |
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0264-9381 |
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| Notes |
WOS:000411741800008 |
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| Call Number |
UAI @ eduardo.moreno @ |
Serial |
800 |
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| Author |
Chandia, O.; Vallilo, B.C. |
| Title |
On-shell type II supergravity from the ambitwistor pure spinor string |
Type |
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| Year |
2016 |
Publication |
Classical And Quantum Gravity |
Abbreviated Journal |
Class. Quantum Gravity |
| Volume |
33 |
Issue |
18 |
Pages |
9 pp |
| Keywords |
supergravity models; superstrings; pure spinor string |
| Abstract |
We obtain all the type II supergravity constraints in the pure spinor ambit-wistor string by imposing consistency of local worldsheet gauge symmetries. |
| Address |
[Chandia, Osvaldo] Univ Adolfo Ibanez Diagonal Las Torres, Fac Ingn & Ciencias, Univ Adolfo Ibanez, Dept Ciencias,Fac Artes Liberales, Santiago 2640, Chile, Email: ochandiaq@gmail.com; |
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| Publisher |
Iop Publishing Ltd |
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English |
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| ISSN |
0264-9381 |
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| Notes |
WOS:000383961300003 |
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| Call Number |
UAI @ eduardo.moreno @ |
Serial |
658 |
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| Author |
Hojman, S.A.; Asenjo, F.A. |
| Title |
Spinning particles coupled to gravity and the validity of the universality of free fall |
Type |
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| Year |
2017 |
Publication |
Classical And Quantum Gravity |
Abbreviated Journal |
Class. Quantum Gravity |
| Volume |
34 |
Issue |
11 |
Pages |
8 pp |
| Keywords |
spin-gravity coupling; spinning massive particle; Lagrangian description |
| Abstract |
Recent experimental work has determined that free falling Rb-87 atoms on Earth, with vertically aligned spins, follow geodesics, thus apparently ruling out spin-gravitation interactions. It is showed that while some spinning matter models coupled to gravitation referenced to in that work seem to be ruled out by the experiment, those same experimental results confirm theoretical results derived from a Lagrangian description of spinning particles coupled to gravity constructed over forty years ago. A proposal to carry out (similar but) different experiments which will help to test the validity of the universality of free fall as opposed to the correctness of the aforementioned Lagrangian theory, is presented. |
| Address |
[Hojman, Sergio A.] Univ Adolfo Ibanez, Fac Artes Liberales, Dept Ciencias, Santiago, Chile, Email: sergio.hojman@uai.cl; |
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| Publisher |
Iop Publishing Ltd |
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| Language |
English |
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0264-9381 |
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Conference |
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| Notes |
WOS:000402399700011 |
Approved |
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| Call Number |
UAI @ eduardo.moreno @ |
Serial |
735 |
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| Author |
Hojman, S.A.; Asenjo, F.A. |
| Title |
Can gravitation accelerate neutrinos? |
Type |
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| Year |
2013 |
Publication |
Classical And Quantum Gravity |
Abbreviated Journal |
Class. Quantum Gravity |
| Volume |
30 |
Issue |
2 |
Pages |
10 pp |
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| Abstract |
The Lagrangian equations of motion for massive spinning test particles (tops) moving on a gravitational background using general relativity are presented. The paths followed by tops are nongeodesic. An exact solution for the motion of tops on a Schwarzschild background which allows for superluminal propagation of tops is studied. It is shown that the solution becomes relevant for particles with small masses, such as neutrinos. This general result is used to calculate the necessary condition to produce superluminal motion in part of the trajectory of a small mass particle in a weak gravitational field. The condition for superluminal motion establishes a relation between the mass, energy and total angular momentum of the particle. |
| Address |
[Hojman, Sergio A.] Univ Adolfo Ibanez, Dept Ciencias, Fac Artes Liberales, Fac Ingn & Ciencias, Santiago, Chile, Email: sergio.hojman@uai.cl; |
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| Publisher |
Iop Publishing Ltd |
Place of Publication |
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| Language |
English |
Summary Language |
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0264-9381 |
ISBN |
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Conference |
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| Notes |
WOS:000313097300008 |
Approved |
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| Call Number |
UAI @ eduardo.moreno @ |
Serial |
257 |
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| Author |
Zalaquett, N.; Hojman, S.A.; Asenjo, F.A. |
| Title |
Spinning massive test particles in cosmological and general static spherically symmetric spacetimes |
Type |
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| Year |
2014 |
Publication |
Classical And Quantum Gravity |
Abbreviated Journal |
Class. Quantum Gravity |
| Volume |
31 |
Issue |
8 |
Pages |
21 pp |
| Keywords |
exact solution; conformally flat spacetimes; spinning massive particle; cosmological spacetimes |
| Abstract |
A Lagrangian formalism is used to study the motion of a spinning massive particle in Friedmann-Robertson-Walker and Godel spacetimes, as well as in a general Schwarzschild-like spacetime and in static spherically symmetric conformally flat spacetimes. Exact solutions for the motion of the particle and general exact expressions for the momenta and velocities are displayed for different cases. In particular, the solution for the motion in spherically symmetric metrics is presented in the equatorial plane. The exact solutions are found using constants of motion of the particle, namely its mass, its spin, its angular momentum, and a fourth constant, which is its energy when the metric is time-independent, and a different constant otherwise. These constants are associated to Killing vectors. In the case of the motion on the Friedmann-Robertson-Walker metric, a new constant of motion is found. This is the fourth constant which generalizes previously known results obtained for spinless particles. In the case of general Schwarzschild-like spacetimes, our results allow for the exploration of the case of the Reissner-Nordstrom-(Anti) de Sitter metric. Finally, for the case of the conformally flat spacetimes, the solution is explicitly evaluated for different metric tensors associated to a universe filled with static perfect fluids and electromagnetic radiation. For some combination of the values of the constants of motion the particle trajectories may exhibit spacelike velocity vectors in portions of the trajectories. |
| Address |
[Zalaquett, Nicolas] Pontificia Univ Catolica Chile, Fac Fis, Santiago 22, Chile, Email: nzalaque@puc.cl; |
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Thesis |
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| Publisher |
Iop Publishing Ltd |
Place of Publication |
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| Language |
English |
Summary Language |
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Edition |
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| ISSN |
0264-9381 |
ISBN |
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Conference |
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| Notes |
WOS:000334418900012 |
Approved |
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| Call Number |
UAI @ eduardo.moreno @ |
Serial |
373 |
| Permanent link to this record |
