| 1. |
- Tamburini, Fabrizio, et al.
(författare)
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Kerr-spacetime geometric optics for vortex beams
- 2021
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Ingår i: Physical Review A: covering atomic, molecular, and optical physics and quantum information. - : American Physical Society. - 2469-9926 .- 2469-9934. ; 104:1
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Tidskriftsartikel (refereegranskat)abstract
- We consider the analogy between gravitational fields and optical media within the framework of geometrical optics in curved spacetime in order to describe how light can acquire orbital angular momentum (OAM) when it traverses the gravitational field of a massive rotating compact object; in particular, we analyze the interplay between OAM and polarization. Kerr spacetimes are known not only to impose a gravitational Faraday rotation on the polarization of a light beam, but also to set a characteristic fingerprint in the orbital angular momentum distribution of the radiation passing nearby a rotating black hole (BH). Kerr spacetime behaves like an inhomogeneous and anisotropic medium, in which light can acquire orbital angular momentum and spin-to-orbital angular momentum conversion can occur, acting as a polarization and phase changing medium for the gravitationally lensed light, as confirmed by the data analysis of the M87* black hole.
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| 2. |
- Tamburini, Fabrizio, et al.
(författare)
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Majorana bosonic quasiparticles from twisted photons in free space
- 2021
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Ingår i: Physical Review A: covering atomic, molecular, and optical physics and quantum information. - : American Physical Society. - 2469-9926 .- 2469-9934. ; 103:3
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Tidskriftsartikel (refereegranskat)abstract
- The speed of light in vacuum, c, is a fundamental constant of nature. Photons belonging to a structured beam of finite transverse size have been observed to travel with a group velocity vg, smaller than c, also when propagating in vacuum. The paradox of slow photons in vacuum could, in a first approach, be explained as a simple projection effect that occurs when one measures the speed of light in a diverging vortex beam along the direction of the beam propagation. This effect, instead, reveals fundamental properties of structured light beams: they form a class of quasiparticle states characterized by the geometric properties of the beams such as the beam divergence, spin angular momentum, orbital angular momentum (OAM), and the group velocity. These anomalous propagation modes with group velocities different than that of c represent a class of Majorana quasiparticles with bosonic spectrum for integer OAM modes, cast in an infinite tower of quasiparticle states similar to those expected with photons propagating in a turbulent plasma.
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| 3. |
- Tamburini, F., et al.
(författare)
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Relativistic Heisenberg principle for vortices of light from Planck to Hubble scales
- 2020
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Ingår i: Physical Review Research. - : AMER PHYSICAL SOC. - 2643-1564. ; 2:3
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Tidskriftsartikel (refereegranskat)abstract
- We discuss, in the relativistic limits, Heisenberg's uncertainty principle for the electromagnetic orbital angular momentum (OAM) of monochromatic fields. The Landau and Peierls relativistic approach applied to the Heisenberg indetermination between the azimuthal angle Delta phi and the OAM state Delta l, when a limit speed is present, exposes the conceptual limits of a possible formulation of the uncertainty principle for OAM states as it leads to the Ehrenfest's paradox of the rotation of a rigid disk in special relativity (SR). To face this problem, in a way similar to Einstein's discussion of a rotating rigid disk, one has to adopt a general relativistic approach and include the limits from smallest and largest scales present in nature, such as the Planck scale and the Hubble horizon.
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| 4. |
- Tamburini, Fabrizio, et al.
(författare)
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Twisted Soft Photon Hair Implants on Black Holes
- 2017
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Ingår i: Entropy. - : MDPI AG. - 1099-4300. ; 19:9
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Tidskriftsartikel (refereegranskat)abstract
- Background: The Hawking-Perry-Strominger (HPS) work states a new controversial idea about the black hole (BH) information paradox, where BHs maximally entropize and encode information in their event horizon area, with no "hair" thought to reveal information outside but angular momentum, mass, and electric charge only in a unique quantum gravity (QG) vacuum state. New conservation laws of gravitation and electromagnetism, appear to generate different QG vacua, preserving more information in soft photon/graviton hair implants. We find that BH photon hair implants can encode orbital angular momentum (OAM) and vorticity of the electromagnetic (EM) field. Methods: Numerical simulations are used to plot an EM field with OAM emitted by a set of dipolar currents together with the soft photon field they induce. The analytical results confirm that the soft photon hair implant carries OAM and vorticity. Results: a set of charges and currents generating real EM fields with precise values of OAM induce a "curly", twisted, soft-hair implant on the BH with vorticity and OAM increased by one unit with respect to the initial real field. Conclusions: Soft photon implants can be spatially shaped ad hoc, encoding structured and densely organized information on the event horizon.
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