Parameter counting for singular monopoles

Parameter counting for singular monopoles

Dieter Van den Bleeken

Boğaziçi Üniversitesi

Abstract : I will motivate the study of non-Abelian monopoles with singular boundary conditions and the study of their semi classical physics. I will then discuss how one particularly important property, the dimension of their moduli space, can be computed.

Yer : MSGSÜ Bomonti Binası, Fizik Bölümü
Tarih : 3 Nisan 2014 Perşembe, 15:00
Ayrıntılı bilgi :

On the cosmological constant problem and its relation to the extrinsic shape of the universe

On the cosmological constant problem and its relation to the extrinsic shape of the universe

Shahram Jalalzadeh

Shahid Beheshti University

Abstract : Within the conventional big-bang cosmological model, it is very difficult to understand why the cosmological constant is so small. In this talk, first, I will discuss a new classical unified field theory (like Kaluza-Klein theories), where Yang-Mills fields have a geometrical origin, arising from twisting vector fields of the non-compact bulk space. Applying this formalism to cosmology, I derive the generalized Friedmann equations. It is also shown that the cosmological constant could actually be the manifestation of the extrinsic shape of the 4D spacetime in the 11D bulk space. The predictions of this model are in good agreement with observations.

Yer : MSGSÜ Bomonti Binası, Fizik Bölümü
Tarih : 27 Mart 2014 Perşembe, 15:00
Ayrıntılı bilgi :

4 Boyutta Kütleli S-Düalite

4 Boyutta Kütleli S-Düalite

E.Ulaş Saka

İstanbul Üniversitesi Fizik Bölümü

Sicim teoriler arasındaki düalite ilişkileri, genel olarak teorilerin zayıf ve güçlü etkileşim bölgeleri arasında  bir gönderim olarak tanımlanır.  Teorilerin farklı kompakt  çokkatlılar üzerine indirgenerek düalite ilişkileri  ve teorilerin barındırdıkları simetriler   zenginleştirilebilmektedir. Ayrıca indirgeme mekanizması akı (kompakt koordinatlara özel bir halde bağlı olarak)   terimi eklenerek yapıldığında alt boyutlarda kütleli süpergravite modelleri elde edilebileceği görülmüştür.  N=4 ve D=4  süpergravite modellerini ayar etmenin genel bir formalizmi Schön ve Weidner tarafından  gösterilmiştir. Dolayısıyla  akı kompaktifikasyon sonucu oluşturulan teorilerin bir ayar süpergravite teorisi olup olmadığı anlaşılabilirdir.  Tip IIA süpergravite teoriye, dilaton , metrik ve NS 2-form alanların ölçeklendirme simetrilerinden yararlanarak  Scherk-Schwarz boyutsal indirgemesi uygulandı. Nihai teori kütleli 2-form ve 1-form alanları içeren  dört boyutta kütleli bir ayar edilmiş yeni bir süpergravite teoridir. Bu teorinin, kütleli 2-form ve vektör alanları  içeren bir teoriye S-dual olduğunu gösterildi. S-dual teorinin Heterotik teorinin Scherk-Schwarz indirgemesi sonucu  ortaya çıktığı görüldü. Buradan hareketle tip IIA ve heterotik teoriler arasında 4 boyutta kütleli S-düalite ilişkisi  kuruldu. Dört boyuttaki söz konusu lagranjiyenin SL(2) simetrisini kısmi olarak taşıyan  ve en genel formu Schön-Weidner tarafından gösterilen N=4 ve D=4 ayar edilmiş Lagranjiyen  formuna getirilebildiği gösterildi.

Yer : MSGSÜ Bomonti Binası, Fizik Bölümü.
Tarih : 16 Mayıs 2013 Perşembe, 15:00
Ayrıntılı bilgi :

The Non-conformal Hydrodynamics in the Einstein-dilaton Theory

The Non-conformal Hydrodynamics in the Einstein-dilaton Theory

Chanyong Park

Center for Quantum Spacetime (CQUeST)

Sogang University, Seoul

Özet/Abstract :
We study a general D-dimensional Schwarzschild-type black brane solution of the Einstein-dilaton theory, whose dual theory, following the generalized gauge/gravity duality,is described by a relativistic non-conformal theory. We study the thermodynamics and the hydrodynamics of such a relativistic non-conformal theory.Furthermore, we discuss about the self-consistency of the gauge/gravity duality in the non-AdS space.

Yer : MSGSÜ Bomonti Binası, Fizik Bölümü.
Tarih : 25 Nisan 2013 Perşembe, 15:00
Ayrıntılı bilgi :

Hadron structure in lattice QCD

Hadron structure in lattice QCD

Güray Erkol

Özyeğin Üniversitesi. İstanbul

Özet : Lattice QCD is a numerical method, which formulates QCD on a space-time lattice allowing us to obtain information about hadron properties from first principles. It has proved to be rather successful in predicting the spectral properties of mesons and baryons, as well as the parameters characterizing their interactions. Nowadays, QCD can be simulated on more realistic setups with the advent of powerful computing resources and numerical techniques. I will talk about our recent simulations where we aim to understand the structure of hadrons and their couplings, with special emphasis on charm hadrons

Yer : MSGSÜ Bomonti Binası, Fizik Bölümü.
Tarih : 24  Ocak 2013 Perşembe, 15:00
Ayrıntılı bilgi :

Gamma-ray spectroscopy at GANIL today and tomorrow

Gamma-ray spectroscopy at GANIL today and tomorrow

Gilles de France

Le Grand Accélérateur National d’Ions Lourds (GANIL)

Özet/Abstract : Gamma-ray spectroscopy is intensively used at GANIL to measure low lying states in exotic nuclei on the neutron-rich as well as on the neutron-deficient side of the nuclear chart. To perform this physics program, the EXOGAM array consisting of hyper pure germanium detectors is routinely used. This detector has been designed to efficiently exploit the low intensity beams delivered by the first generation of facility producing and accelerating radioactive nuclei. After many years of operation using both stable and radioactive beams at GANIL, EXOGAM has been moved for six months at the ILL Grenoble to perform the spectroscopy of fission fragments produced in the cold fission of actinide targets. In parallel, a very significant upgrade of the electronics is going on which will multiply the capabilities of the array. An overview of the array will be given together with the ongoing electronics development. The physics program both at GANIL and at the ILL will be evoked. In addition SPIRAL2, a second generation ISOL facility, is under construction at GANIL. A brief overview of the future accelerator complex will be given and discussed.

Yer : MSGSÜ Bomonti Binası, Fizik Bölümü.
Tarih : 13 Aralık 2012 Perşembe, 15:00
Ayrıntılı bilgi

Critical nature of plastic flow

Critical nature of plastic flow

Oguz Umut Salman

Ecole Polytechnique Paris

Özet/Abstract : Steady plastic flows have been compared to developed turbulence because the two phenomena share the inherent complexity of particle trajectories, the scale free spatial patterns and the power law statistics of fluctuations. The presence of power law distributions has been interpreted as a sign of criticality, marginal stability and scale free behavior of the underlying microscopic systems. In this talk we present a simple mathematical model which is capable of generating power law signals with critical exponents matching observations. Our main conclusion is the existence of a discrete automaton behind the conventional continuum mechanical equations.

Yer : MSGSÜ Bomonti Binası, Fizik Bölümü.
Tarih : 11 Ekim 2012 Perşembe, 15:00

The tasks and perspectives of stringy theory of knots

The tasks and perspectives of stringy theory of knots

Alexei Morozov

ITEP Moscow

04.10.2012 Thursday/Perşembe 15:00

Place/Yer : MSGSÜ Bomonti Binası, Fizik Bölümü.
İnfo/Bilgi :

Acoustic superradiance from a vortex in Bose – Einstein condensates

Acoustic superradiance from a vortex in Bose – Einstein condensates

Nader Ghazanfari

Koç University, Physics Dept., İstanbul

27.09.2012 Thursday/Perşembe 15:00

Özet/Abstract : Unruh’s efforts to make a connection between propagation of sound in non-homogenous media and propagation of light in curved space time resulted in surprising systems appropriate for studying different features of the black holes such as spontaneous radiation and stimulated emissions. Acoustic superradiance is the analogue of Penrose process as a stimulated emission which is the extraction of energy from a rotating black hole. This process occurs in curved spacetime that is the geometry of rotating black holes. Event horizon in such a spacetime exists inside a region called ergoregion, and since the rotating energy of the black hole is located in between event horizon and ergosphere the extracting of energy becomes possible. In other words, in this process, the wave solution of the field equation is scattered from ergo region with an increase in its amplitude. Vortex geometry could be a nice analogue of a black hole in order to observe Penrose process since it reveals an effective ergo region which is also simple to be achieved is experiments.

Place/Yer : MSGSÜ Bomonti Binası, Fizik Bölümü.
İnfo/Bilgi :