1 MAY 2024
17:30 - 19:00

A special case of Hironaka's QUESTION F, named F', asks about the strong factorization of birational maps between reduced nonsingular algebraic schemes, which is still open. Suppose that $varphi : Xdashrightarrow Y$ is such a map, and let $Usubset X$ be the open subset where $varphi$ is an isomorphism. This problem asks if there exists a diagram $$xymatrix{ & Z ar[dl]_{varphi_{1}}ar[dr]^{varphi_{2}}X ar[rr]^{varphi} & & Y}$$ where the morphisms $varphi_{1}$ and $varphi_{2}$ are sequences of blow-ups of non-singular centers disjoint from $U$. In this talk, we will discuss how strong factorization can be simplified by providing a complete answer to the problem of toroidalization of morphisms, while we introduce the strong Oda conjecture.

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Meeting ID: 9086116889
Passcode: 362880
Venue: , (Online)

1 MAY 2024
14:00 - 15:00

The orthodox many-body theory of atoms, molecules and condensed phases is the electronic structure theory plus the theory of nuclear vibrations and rotations. The basic tent of this theory is the Born-Oppenheimer separation of the electronic and nuclear dynamics through deriving two Schrodinger equations, one for electrons, and the other for nuclei. The electronic Schrodinger equation, which conceives electrons as the sole quantum particles within the external field produced by clamped nuclei, yields the electronic eigenvalues, i.e. the potential energy surfaces, and the electronic eigenfunctions. On the other hand, the nuclear Schrodinger equation, which conceives nuclei as quantum particles experiencing the potential energy surfaces as the effective potentials, yields the eigenvalues and eigenstates of the collective vibrational and rotational modes. An unorthodox but more general reformulation of the many-body theory, called the multi-component quantum chemistry, dismisses the Born-Oppenheimer separation totally and the resulting many-body system is governed by a single multi-component Hamiltonian encompassing all interactions between electrons and nuclei. Theoretically, the resulting multi- component theory contains the orthodox theory as a special case thus one intuitionally expects it must be capable of reproducing the concepts and numerical results derived within the context of the orthodox many-body theory. In contrast, various theoretical arguments and computational studies, particularly in the last two decades, reveal exotic features of the multi-component quantum chemistry theory incompatible with the results derived from the orthodox many-body theory. In this talk I will introduce the basic tents of the multi-component quantum chemistry at a non-technical level as well as some of its paradoxical features by considering some illustrative examples. Some selected applications of the theory are also briefly considered including the status of nuclear quantum-superposed states in molecular systems and the newly discovered positronic bonds.


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https://www.skyroom.online/ch/schoolofnanoscience/weeklyseminars

1 MAY 2024
14:00 - 15:00

Given two graphs $H$ and $G$‎, ‎the size multipartite Ramsey number $ m_j (H,G )$ is the smallest natural number $t$ such that an arbitrary coloring of the edges‎ ‎of $K_{j imes t}$‎, ‎complete multipartite graph whose vertex set is partitioned into $j$ parts each of size $t$‎, ‎using two colors red and blue‎, ‎necessarily forces a red copy of $H$ or a blue copy of $G$ as a subgraph‎. ‎The notion of size multipartite Ramsey number has been introduced by Burger and Vuuren in 2004‎. ‎It is worth noting that‎, ‎this concept is derived by using the idea of the original classical Ramsey number‎, ‎multipartite‎ ‎Ramsey number and the size Ramsey number‎. ‎\‎ ‎Recently‎, ‎we determined the order of magnitude of size multipartite Ramsey numbers of graphs $K_m$ and $K_{1,n}$ ($m_j(K_m‎, ‎K_{1,n})$)‎. ‎Indeed‎, ‎we found a lower and an upper bound for $m_j(K_m‎, ‎K_{1,n})$‎, ‎for every positive integers $j‎, ‎m$ and $n$‎. ‎We showed that the upper bound is tight‎. ‎We also found the exact values of $m_j({K_m‎, ‎K_{1,n}})$ when $m=3$‎, ‎$j=m$ and $ m-1 | j$‎.

Zoom room information is:
https://us06web.zoom.us/j/89600366073?pwd=RMHt0eGdvGtkaDBG1Me3y8bOLgooGh.1
Meeting ID : 896 0036 6073
Passcode : 290109
Venue: Niavaran, Lecture Hall 1

1 MAY 2024
13:30 - 15:00

In this blackboard talk I will show how the nature of thermalization may be probed by the Krylov basis.

1 MAY 2024
15:30 - 17:00

The interplay of the geometric and the spectral properties of Riemannian manifolds are highly influential in essentially all areas of mathematics, but are far from being fully understood. Some of the recent advancements in understanding this relation could be achieved by means of transfer operators. I shall overview some recent developments in this area with a focus on hyperbolic surfaces, automorphic functions, resonances and the dynamics of the geodesic flow and with an emphasis on insights and heuristics. In particular, I will, at the example of Hecke triangle groups, discuss how an outer symmetry in the dynamics translates into a parity for automorphic functions.

Location: https://meet.google.com/you-qymk-ybu
Venue: , (Online)

29 APR 2024
16:00 - 18:00

Moral Particularism and the Prospects of Machine Ethics

28 APR 2024
15:00 - 16:00

Abstract:

We study the null brane and its quantization. We show that there are 2 important constraint classes. One is the extension of the level-matching constraint to the brane case. The other constraint, which is specific to the brane is more involved and poses the main source of difficulty in quantizing the null brane. We have found three classes of physical states, depending on their eigenvalues under level-matching operator, that can satisfy the constraints. The trivial one constitutes zero-eigenstates of level-matching operator, which we call Class-1. We show that this class trivially satisfies the brane-sourced constraint as well as level-matching. There exists another, more involved and interesting class of states that are not zero-eigenstates of the level-matching operators. We study their structure and also describe how we can satisfy the brane-sourced constraint for these states.

Meeting Place:
Seminar Room, School of Particles and Accelerators, IPM

Link to Join Virtually:
https://meet.google.com/fnv-dfkk-ghb

24 APR 2024
11:00 - 12:00

Abstract:

Optical vortex beams are of fundamental interest due to their applications. An optical vortex with a spiral phase carries an orbital angular momentum (OAM) along the propagation axis . There is a phase singularity at the core of the vortex which evolves its doughnut-shaped intensity profile. Optical vortices are routinely created to carry specific values of OAM. When interacting with the matter, their specific characteristics result in various interesting effects, including ultraprecise atom localization, entanglement of OAM states of photon pairs, atom vortex beams, light-induced torque and spatially dependent electromagnetically induced transparency (EIT). A transition from a nontrivial (vortex) to a trivial (nonvortex) state of the light is very promising and may provide interesting applications in the topological photonic area. The exchange of optical vortices is a possible tool for the manipulation of information encoded into the OAM of light. It allows generating structured light at a wavelength for which it is not possible to do it directly with standard optics (e.g., far infrared or UV).


Indico Link:
https://indico.hep.ipm.ir/e/h.asadpour

Link to join the webinar:
https://meet.google.com/fnv-dfkk-ghb