Tbilisi, Georgia
Tbilisi, Georgia

The Free University of Tbilisi is a private university established in 2007 via the merge of ESM Tbilisi and the Tbilisi Institute of Asia and Africa. The main goal of Kakha Bendukidze, FreeUni's founder, was providing opportunities for a quality education for every motivated adult, regardless of financial conditions, believing that clarity of purpose and the future were essential to any human endeavour.The Free University is organized into 7 constituent schools: the Institute of Asia and Africa , Business, Law, Computer science and Maths, Visual Arts and Design, Governance and Social science, Physics and Law Schools. While the Free University is governed by a combination of its Board of Overseers and the Knowledge Foundation, each school's faculty oversees its curriculum and degree programs. In addition to a central campus shared with Agricultural University of Georgia in downtown Tbilisi, the University owns facilities all around Georgia, including Anaseuli Education Center.The current Rector of The Free University is prof. Guram Chikovani. There are 56 full-time and 84 part-time lecturers. 44 hold PhDs; 25 are PhD students. The programs are run on a daily basis by deans and academic coordinators.The University consists of 7 Schools: Institute of Asia and Africa ESM Law School MACS Physics School GOV Visual Arts and Design School / VADS.↑ ↑ ↑ ↑ Wikipedia.

Time filter

Source Type

Osmanov Z.,Free University of Tbilisi | Rieger F.M.,University of Heidelberg | Rieger F.M.,Max Planck Institute for Nuclear Physics
Monthly Notices of the Royal Astronomical Society | Year: 2017

The Crab Pulsar has been recently detected at very high energies (VHE) with its pulsed VHE emission reaching up to 1.5 TeV. The VHE peaks appear synchronized with the peaks at GeV energies and show VHE spectra following hard power-law functions. These new findings have been interpreted as evidence for a γ -ray production that happens very close to the light cylinder. Motivated by these experimental results, we consider the efficiency of magnetocentrifugal particle acceleration in the magnetosphere of the Crab Pulsar, reexamining and extending results obtained in a previous work. It is shown that efficient magnetocentrifugal acceleration close to the light cylinder could provide the required electron Lorentz factors of 5 × 106 and that the resulting inverse Compton (IC) scattering off thermal photons might explain the enigmatic TeV emission of the pulsar. We estimate the corresponding VHE luminosity and provide a derivation of its spectral characteristics that appear remarkably close to the observational results to encourage further studies. © 2016 The Authors.

News Article | May 16, 2017
Site: phys.org

With missions that are now capable of locating extra-solar planets (i.e. the Kepler Space Observatory) scientists have been on the lookout for signs of possible alien megastructures. Unfortunately, aside from some very arguable results, no concrete evidence has yet come to light. Lucky for us, in a study from the Free University of Tbilisi, Professor Zaza Osmanov offers some new insight on why megastructures may have eluded us so far. While fascinating, the idea of alien megastructures invariably suffers from the same problem as all other attempts to find signs of intelligent life in our Universe. Basically, if intelligent life exists, why have we consistently failed to find any evidence of it? This conundrum, which was summed up by Enrico Fermi in the 1950s (thereafter known as the Fermi Paradox), has hung like a shadow over all our efforts. For example, in the summer of 2015, a team of astronomers announced that they found what might be an indication of an alien megastructure around Tabby's Star (KIC 8462852). However, they were quick to point out that any number of possibilities could explain the strange dimming pattern coming from the star, and subsequent studies offered even more plausible explanations – such as the star having consumed a planet at some point in its past. To this, Osmanov has argued that the problem is that we are looking in the wrong places. Last year, he wrote a research paper in which he ventured that an alien super civilization – i.e. one that was consistent with a Level II Kardashev civilization – would likely use ring-like megastructures to harness the power of their stars. This is in contrast to the traditional concept of a "Dyson's Sphere", which would consist of a spherical shell. Furthermore, he argued that these Dyson Rings would likely be built around pulsars rather than stars, and offered estimates on their dimensions which were dependent on the rotational speed of the pulsar. According to Osmanov's latest study, titled "Are the Dyson rings around pulsars detectable?", Osmanov extends the problem of spotting alien megastructures to the observational realm. Specifically, he addressed how alien megastructures could be spotted by identifying their infrared energy signatures, and at what kinds of distances. By examining how such structures would vary in terms of the amount of IR radiation they would emit, he believes that they could be spotted within our local Universe using existing instruments. Once again, it comes down to the diameter of the structures, which would in turn depend on the type of pulsar they orbit. As he states in the paper: "A couple of years earlier before publishing the paper of Kardashev, the prominent physicist Freeman Dyson has suggested that if such superadvanced (in the terminology of Kardashev, Level-II) extraterrestrials exist, for increasing efficiency of energy consumption they can construct a thin spherical shell with radius ?1AU surrounding a host star (Dyson 1960). It has been argued that for such distances the sphere will be in the so-called habitable zone (HZ) and therefore the sphere will have the temperature of the order of (200 – 300 K), making this object visible in the infrared spectrum." Extending this to pulsars, Osmanov estimates that the habitable zone around a relatively slowly-rotating pulsar (with a period of about half a second) would be on the order of 0.1 AU. According to his calculations, a ring-like megastructure that orbited a pulsar at this distance would emit temperatures on the order of 390 K (116.85 °C; 242.33 °F), which means that the megastructure would be visible in the IR band. From this, Osmanov concludes that modern IR telescopes – such as the Very Large Telescope Interferometer (VLTI) and the Wide-field Infrared Survey Explorer (WISE) – would have the necessary capacity to monitor nearby pulsars for signs of alien megastructures. He further concludes that for this purpose, these telescopes would have an effective range of up to 200 parsecs (~652 light years). In addition, he goes on to state that within this volume of space, multiple candidates could be found and examined using these same existing instruments: "We have considered the sensitivity of VLTI and by taking into account its higher possible angular resolution, 0.001 mas, it has been shown that the maximum distance ~0.2 kpc leads to the IR spectral density of the order of 7.4 mJy, which in turn, can be detected by the VLTI. We have argued that by monitoring the nearby zone of the solar system approximately 64 pulsars are expected to be located inside it." Beyond these distances, up to the kiloparsec range (about 3260 light years), the angular resolution of these telescopes would not be enough to detect the structure of any rings. As such, finding megastructures at this distance would require telescopes that can conduct surveys in the UV band – which corresponds to the surface temperatures of neutron stars (7000 K). However, this would have to wait upon the development of more sensitive instruments. "As we see, the search of infrared rings is quite promising for distances up to -0.2 kpc, where one will be able to monitor potentially 64 ± 21 pulsars by using the IR instruments," he concluded. "Observation of distant pulsars (up to -1kpc), although will significantly increase the total number of potential objects – to 1600 ± 530, but at this moment the UV instruments cannot provide such a level of sensitivity." So while the range would be limited, the opportunities for testing this hypothesis would not. All told, between 43 and 85 candidates exist within the observable volume of space, according to Osmanov's estimates. And with existing IR telescopes – and next-generation telescopes like the James Webb Space Telescopes – up to the task, some surveys could be conducted that would yield valuable information either way. The concept of alien megastructures remains a controversial one, and for good reason. For one, the potential evidence for such structures – i.e. the periodic dimming of a star – can easily be explained by other means. Second, there is an undeniable degree of wishful thinking when it comes to the search for extra-terrestrial intelligence, which means that any findings could be subject to bias. Nevertheless, the search for intelligent life remains a very fascinating field of study, and a necessary one at that. Not only would finding other examples of life in our Universe put to rest one of the most burning existential questions of all time – are we alone? – it would also allow us to learn a great deal about what other forms life could take. Is all life carbon based, are there other possibilities, etc? We would like to know! In the end, the Fermi Paradox will only be resolved when we find definitive evidence that there is intelligent life out there other than our own. In the meantime, we can expect that we will keep searching until we find something. And anything that make this easier by telling us where we should (and what specifically to look for) is sure to help. Explore further: Breakthrough Listen to search for intelligent life around weird star More information: Are the Dyson rings around pulsars detectable? arxiv.org/abs/1705.04142

Kakushadze Z.,Quantigic Solutions LLC | Kakushadze Z.,Free University of Tbilisi
Journal of Informetrics | Year: 2016

We propose a new index to quantify SSRN downloads. Unlike the SSRN downloads rank, which is based on the total number of an author's SSRN downloads, our index also reflects the author's productivity by taking into account the download numbers for the papers. Our index is inspired by - but is not the same as - Hirsch's h-index for citations, which cannot be directly applied to SSRN downloads. We analyze data for about 30,000 authors and 367,000 papers. We find a simple empirical formula for the SSRN author rank via a Gaussian function of the log of the number of downloads. © 2015 Elsevier Ltd.

Chkheidze N.,Ilia State University | Machabeli G.,Ilia State University | Osmanov Z.,Free University of Tbilisi
Astrophysical Journal | Year: 2013

In the present paper, a self-consistent theory, interpreting VERITAS and the MAGIC observations of the very high-energy pulsed emission from the Crab pulsar, is considered. The photon spectrum between 10 MeV and 400 GeV can be described by two power-law functions with spectral indices of 2.0 and 3.8. The source of the pulsed emission above 10 MeV is assumed to be synchrotron radiation, which is generated near the light cylinder during the quasi-linear stage of the cyclotron instability. The emitting particles are the primary beam electrons with Lorentz factors up to 109. Such high energies of beam particles can be reached due to Landau damping of the Langmuir waves in the light cylinder region. © 2013. The American Astronomical Society. All rights reserved.

Osmanov Z.,Free University of Tbilisi | Chkheidze N.,Ilia State University
Astrophysical Journal | Year: 2013

In the present paper, we study the generation of synchrotron emission by means of the feedback of Cherenkov-drift waves on the particle distribution through the diffusion process. Despite the efficient synchrotron losses, it is demonstrated that the excited Cherenkov-drift instability leads to the quasi-linear diffusion (QLD), the effect of which is balanced by dissipation factors and, as a result, the pitch angles are prevented from damping, thus maintaining the corresponding synchrotron emission. We analyze the model for a wide range of physical parameters and determine that the mechanism of QLD guarantees the generation of electromagnetic radiation from soft X-rays up to soft γ-rays, which is strongly correlated with Cherenkov-drift emission ranging from IR up to UV energy domains. © 2013. The American Astronomical Society. All rights reserved.

Osmanov Z.,Free University of Tbilisi
International Journal of Astrobiology | Year: 2016

Assuming the possibility of existence of a supercivilization we extend the idea of Freeman Dyson considering pulsars instead of stars. It is shown that instead of a spherical shell the supercivilization must use ring-like constructions. We have found that a size of the 'ring' should be of the order of (10-4-10-1) AU with temperature interval (300-600) K for relatively slowly rotating pulsars and (10-350) AU with temperature interval (300-700) K for rapidly spinning neutron stars, respectively. Although for the latter the Dyson construction is unrealistically massive and cannot be considered seriously. Analyzing the stresses in terms of the radiation and wind flows it has been argued that they cannot significantly affect the ring construction. On the other hand, the ring in-plane unstable equilibrium can be restored by the energy which is small compared with the energy extracted from the star. This indicates that the search for infrared ring-like sources close to slowly rotating pulsars seems to be quite promising. © 2015 Cambridge University Press.

Osmanov Z.,Free University of Tbilisi
Monthly Notices of the Royal Astronomical Society | Year: 2014

In this paper, we study the possibility of generation of electromagnetic waves in the magnetospheres of radio magnetars by means of the quasi-linear diffusion (QLD). Considering the magnetosphere composed of the so-called beam and the plasma components, respectively, we argue that the frozen-in condition will inevitably lead to the generation of the unstable cyclotron modes. These modes, via the QLD, will in turn influence the particle distribution function, leading to certain values of the pitch angles, thus to an efficient synchrotron mechanism, producing radio photons. We show that for three known radio magnetars, the QLD might be a realistic mechanism for producing photons in the radio band. © 2014 The Author.

Zaza O.,Free University of Tbilisi
International Journal of Modern Physics D | Year: 2016

In this paper, we study the efficiency of particle acceleration in the magnetospheres of stellar mass black holes. For this purpose, we consider the linearized set of the Euler equation, continuity equation and Poisson equation, respectively. After introducing the varying relativistic centrifugal force, we show that the charge separation undergoes the parametric instability, leading to generation of centrifugally-excited Langmuir waves. It is shown that these waves, via the Langmuir collapse damp by means of the Landau damping, as a result, energy transfers to particles accelerating them to energies of the order of (Formula presented.) eV. © 2017 World Scientific Publishing Company

Osmanov Z.,Free University of Tbilisi
Monthly Notices of the Royal Astronomical Society | Year: 2016

In this paper, we study the generation of very high energy (VHE) emission in Crab-like pulsars driven by means of the feedback of Cherenkov drift waves on distribution of magnetospheric electrons. We have found that the unstable Cherenkov drift modes lead to the quasi-linear diffusion, keeping the pitch angles from vanishing, which in turn, maintains the synchrotron mechanism. Considering the Crab-like pulsars it has been shown that the growth rate of the Cherenkov drift instability is quite high, indicating high efficiency of the process. Analysing the mechanism for the typical parameters we have found that the Cherenkov drift emission from the extreme UV to hard X-rays is strongly correlated with the VHE synchrotron emission in the GeV band. © 2015 The Author.

Osmanov Z.,Free University of Tbilisi
International Journal of Modern Physics D | Year: 2013

We study the influence of the centrifugally driven curvature drift instability (CDI) on the dynamics of relativistic electrons in the magnetospheres of active galactic nuclei (AGN). We generalize in our previous paper by considering relativistic particles with different initial phases. Considering the Euler continuity and induction equations, by taking into account the resonant conditions, we derive the growth rate of the CDI. We show that due to the centrifugal effects, the rotational energy is efficiently pumped directly into the drift modes, that leads to the generation of a toroidal component of the magnetic field. As a result, the magnetic field lines transform into such a configuration when particles do not experience any forces and since the instability is centrifugally driven, at this stage the CDI is suspended. © 2013 World Scientific Publishing Company.

Loading Free University of Tbilisi collaborators
Loading Free University of Tbilisi collaborators