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Physics Colloquium Series

Physics Colloquium presents a venue for the latest developments in all branches of physics in a way accessible to non-expert physicists. The monthly Physics Colloquia take place on selected Wednesdays at 4:30 pm in the Conference Hall of the main Farmanieh building, with an announcement circulated in advance. Please forward your suggestions for potential Colloquium speakers to jabbari(at)theory.ipm.ac.ir. To subscribe to the Colloquium mailing list, please send an email with the subject line "subscribe me to physics colloquium" to physoffice(at)theory.ipm.ac.ir.

Wed May 15, 2024 (1403/2/26)

	May 15 1403/2/26	18:00	Investigation of the Heisenberg's Uncertainty Principle and the Entropy Uncertainty Relation Show Abstract Abstract:Quantum mechanics provided precise and accurate explanations for the experiments conducted at the end of the 19th century. This led to the rapid development of quantum mechanics between 1905 and 1923, capturing the scientific community's attention. At the Solvay Conference in 1927, Werner Heisenberg, a leading figure of the Copenhagen interpretation, presented the uncertainty principle within quantum mechanics. In this lecture, we will explore the significance of Heisenberg's uncertainty principle, discuss a fundamental problem in its original formulation, and introduce the entropy uncertainty relation as an alternative. Furthermore, we will investigate into quantum entanglement and quantum discord, highlighting their crucial roles in precisely determining entropy uncertainty relation. Lecturer(s): Shahriar Salimi From : University of Kurdistan Research Group: Physics Colloquium More Info. : Link
Wed Jan 17, 2024 (1402/10/27)

	Jan 17 1402/10/27	14:00	Role of Love in the Evolution of Cognition Show Abstract Abstract:Novel features emerge from changes in the state and complexity of matter. Physical, chemical and biological principles govern these changes. Brain is the most complex matter known to humans. It emerged over 500 million years ago and has now evolved into its most complex form: the human brain. During this time, as more complex neural structures evolved, novel cognitive capacities have emerged. Through this process, adaptation and natural selection have prompted the evolution of animals with larger brains. On the other hand, large brains need to continue to grow for several years after birth requiring maternal care and love. The basic biological features necessary for the emergence of maternal love were gradually evolved over the course of 70 million years leading to the emergence of maternal love in the early mammals 180 million years ago. The expansion of brain structures responsible for maternal love has prompted the emergence of other social emotions and cognitions such as empathy, trust, romantic love, mystical love, and moral cognition. In this talk I will explain the highlights of this evolutionary process that has shaped our cognitive and emotional world. Lecturer(s): Hossein Esteky From : Shahid Behesti Medical School Research Group: Physics Colloquium More Info. : Poster
Wed Oct 18, 2023 (1402/7/26)

	Oct 18 1402/7/26	18:00	Overviewing metaethics of the last century Show Abstract Abstract:Ethical properties concern what ought to be, rather than what is, and therefore, they appear distinct from natural properties. Metaethics is the study of the foundation of ethics and normativity in general. In this talk, I will provide an overview of the major positions taken in the last century in metaethics. Broadly speaking, this field is divided between those who deny the existence of ethical properties independent of us and those who affirm the existence of a mind-independent ethical realm. Throughout the talk, I will discuss how these two camps have articulated their viewpoints in various ways and explore the significant challenges faced by each formulation. Lecturer(s): Amir Saemi From : School of Philosophy Research Group: Physics Colloquium More Info. : Link
Sat Oct 14, 2023 (1402/7/22)

	Oct 14 1402/7/22	15:00	Amazing neutrino particles Lecturer(s): Yasaman Farzan From : IPM, School of Physics Research Group: Physics Colloquium More Info. : Link
Thu Sep 07, 2023 (1402/6/16)

	Sep 07 1402/6/16	18:00	Modeling Humoral Immune Response to SARS-CoV-2 and Machine Learning for Discriminating COVID-19 and Influenza Infection: An Application Approach Show Abstract Abstract:Mechanistic modelling approaches have become essential in systems biology, enabling the description of known physiological processes and filling gaps in our understanding of complex interactions driving host-pathogen responses. These models provide valuable insights for public health planning and infectious disease control. In this colloquium, I will first present our mathematical model to investigate humoral (antibody-mediated) immunity. B cells and their antibodies play a crucial role in protecting against COVID-19. However, the decline of antibodies following natural infection or vaccination results in reduced defence against subsequent SARS-CoV-2 infections. To comprehend the dynamics of antibody production from B cells, we constructed a computational biology model that incorporates B cells, IgG-neutralizing antibodies, and host-pathogen interactions. This model provides insights into the kinetic processes and mechanisms that drive the humoral response to SARS-CoV-2, including the initiation of B cell responses, differentiation into germinal center cells, long-lived plasma cells, and memory cells. It enhances our understanding of antibody production in primary and secondary reactions. Next, I will present our recent work that centers around applying mathematical modelling to generate synthetic data of influenza and COVID-19 patients, enabling differentiation between the two infections. Here, we developed and validated a supervised machine-learning model utilizing mechanistic models of viral infection. Our investigation showcases the effectiveness of machine learning models in accurately discerning between these diseases by leveraging essential factors related to viral infection and immune response. This model has the potential to serve as a cost-effective classification system, eliminating the need for expensive virus typing procedures and relying solely on viral load and interferon measurements. Lecturer(s): Suzan Farhang-Sardroodi From : University of Manitoba, UniversitÃ© de MontrÃ©al and York University Research Group: Physics Colloquium More Info. : Link
Wed Jul 12, 2023 (1402/4/21)

	Jul 12 1402/4/21	18:00	New experimental and theoretical information on the inner structure of proton Show Abstract Abstract:Proton is the main building block of visible matter. Although we have some information about its physical properties, its inner structure is not clear yet. There are also some puzzles regarding its spin, radii (charge, mass and mechanical), distribution of charge and magnetization inside as well as origin of its mass. In this talk I will discuss these issues introducing different form factors (electromagnetic, gravitational, etc) and generalized parton distributions (GPDs) of proton. I will also address the new experimental and theoretical findings about the quark-gluon organization and shape of the proton. Lecturer(s): Kazem Azizi From : University of Tehran Research Group: Physics Colloquium More Info. : Video
Wed Jun 14, 2023 (1402/3/24)

	Jun 14 1402/3/24	18:00	Hydrogen Generation via Photoelectrochemical Water Splitting on Nanostructure Semiconductors: Physics and Technology Show Abstract Abstract:According to statistics, the total world energy consumption is ~ 5.8 x 1020 J and the world energy demand is expected to double by 2050 with the increase in the population (1.12% per year). In this context, about 83% of today's energy supply originates from fossil fuels (e.g. petroleum, gas and coal) that are responsible for discharging a large amount of CO2 in the environment after their combustion. The release of CO2 accounts for ~ 76% of annual greenhouse gas (GHG) emissions which creates severe problems for environment and public health such as global warming and climate changes. Thus, it is an urgent need to develop efficient methods and consume renewable energy for safer society and sustainable development. The water and sunlight (the amount of solar energy strikes the Earth surface continuously is ~ 5.3 x 1024 J, that is ~ 10,000 times higher than the world's total energy use) are of the most abundant natural resources on the Earth that can be applied to produce clean energy in order to achieve net zero emissions. After a brief history and introduction on principles of semiconductor - based photocatalysis, physics and technology of hydrogen generation via photoelectrochemical (PEC) water splitting on different photocatalysts including nanostructure (0D, 1D and 2D) semiconducting materials, heterostructures, novel 2D materials and hierarchical nanostructures will be discussed. Then various strategies on materials design and optimization as well as recent advances on solar H2 production are introduced. Finally, kinetics and mechanism of the PEC derived H2 production reaction on semiconductor surfaces/interfaces under Ultraviolet - Visible photoirradiation will be discussed. Lecturer(s): Alireza Moshfegh From : Sharif University of Technology Research Group: Physics Colloquium More Info. : Video
Wed May 10, 2023 (1402/2/20)

	May 10 1402/2/20	18:00	Uncovering hidden neuronal microcircuits using Boltzmann like correlations, a unified framework Show Abstract Abstract:The information transfer and processing in our brain relies on cells called neurons. They are connected to each other through connections called synapse, and form an interconnected complex network, known as gray matter. Each neuron receives signals from its upstream neurons, generates a spike, and passes it to many downstream neurons. To understand this complex structure, one should have learnt the connectivity map of neurons, in a living brain. However, it is practically impossible to record from one neuron and all its hidden inputs to determine the influential synapses which dominate the activity of that neuron. Although there are methods to find the connectivity among recorded (observed) neurons, the majority of downstream neurons remain unobserved. Here, we find the analytical input-output relation which describes how a specific input to a neuron controls statistics of its spiking pattern. Then, using this analytics, we connect the hidden microcircuits which are shared by two or more neurons with the observed correlation between their spiking patterns. We present a guide map in the space of neural interactions (i.e pairwise and triple-wise correlations) to infer the influential hidden circuits from data. We verify the validity of the guide map by extensive simulations, using multicompartmental neuron models of Blue Brain Project. Applying the guide map to monkey and mouse, we observed the hidden circuitry of excitatory inputs shared between each pair of three neurons is the motif behind most of the data. We hope experimentalists use our guide-map, to reveal the hidden microcircuits behind their data. Lecturer(s): Seyyed Nader Rasuli From : IPM, School of Physics Research Group: Physics Colloquium More Info. : Link
Wed Apr 06, 2022 (1401/1/17)

	Apr 06 1401/1/17	18:00	Uncovering Energetic Processes in the Interstellar/Intergalactic Medium with the Square Kilometre Array Show Abstract Abstract:Investigating the physics and energetic of the medium where galactic structures, on various scales, are formed is the most fundamental step to understand the formation and evolution of galaxies. Modern galaxy evolution models suggest gas accretion from the intergalactic medium (IGM) or from cosmic filaments as a mechanism to maintain star formation and active galactic nucleus (AGN). Through gas heating and/or gas removal, these models also propose supernova feedback and AGN feedback as mechanisms to quench massive star formation. Observational studies, however, have not reached to a conclusive result showing that feedback can, in some cases, trigger star formation, leaving the issue as an open challenge. It seems that some basic concepts about the formation of structures in the interstellar medium (ISM) and the IGM are missed: What are physical parameters/agents governing the structure formation on various scales? How does the ISM/IGM energy balance change over cosmic time? The advent of the square kilometre array (SKA) and its instrumental capabilities tracing the most energetic ISM components has opened a new window shedding light on the issue. The SKA's sensitive radio continuum observations will trace high-energy particles and magnetic fields not only in star forming regions and AGNs, but also in more quiescent regions in molecular clouds and diffuse IGM, enabling us to study the role of magnetic fields/cosmic rays in structure formation. Sensitive radio continuum observations on large scales may also bring constrains on the entity of dark matter mapped by the Hubble Space Telescope (HST) and Dark Energy Camera (DECam). Lecturer(s): Fatemeh Tabatabaei From : IPM, School of Astronomy Research Group: Physics Colloquium More Info. : Link
Wed Mar 02, 2022 (1400/12/11)

	Mar 02 1400/12/11	18:00	Dance of Cause and Effect: Fluctuation Induced Reduction of Dissipation in Classical Fluids Show Abstract Abstract:About seventy years ago, G I Taylor noticed that the tails of two closely swimming spermatozoa, oscillate in a synchronized fashion as if both of them are controlled from one regulating center. The two sperms, on the other hand, has no mean of communication, but the viscous fluid in which they are swimming. To address the why question, behind the observation, he suggested the minimization of total dissipation in the viscous medium. Sixty years later, Taylors original idea was put to more detailed analytical investigations; non-intuitively, it failed to attribute the observed synchronization to the expected reduction of dissipation. We begin with a very different problem: (a) The motion of two passively trapped beads, which interact through hydrodynamic interactions, and face a driven flow. Both theoretically and experimentally we observe that they almost follow the very motion they would have, if they were to swim on their own in the opposite direction of the driven flow. Calling the phenomenon, the reverse dance, we successfully attribute it to the reduction of the total dissipation. We then (b) extend the minimalistic approach, to two sets of beads; each supposed to mimic the tail of one spermatozoon. Facing a driven flow, on top of their intrinsic oscillation, this is a minimalistic model to verify Taylors idea. The question is, does this simple model lead us to synchronization as well as reduction of fluids dissipation? And if so, can it explain why Taylors original model failed to correctly attribute synchronization with reduction of dissipation? Lecturer(s): Seyyed Nader Rasuli From : University of Guilan & School of Physics, IPM Research Group: Physics Colloquium More Info. : Link
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