У оквиру СЦЛ семинара Центра за изучавање комплексних система, у среду, 24. априла у 11 часова у читаоници библиотеке „Др Драган Поповић“, проф др Ливиу Кионћел (Augsburg Center for Innovative Technologies, and Center for Electronic Correlations and Magnetism, Theoretical Physics III, Institute of Physics, University of Augsburg) ће одржати предавање:

Ab-initio typical-medium single-site theory for disordered systems

САЖЕТАК:

We introduce a self-consistent method to perform electronic structure calculations of disordered systems. The approach employs the single-site typical medium theory and is formulated in the language of multiple scattering. We present the formalism, implementation details and applications for realistic materials in which we find characteristics of Anderson localization, i.e., extended states and localized levels in different regions of the impurity bands.

У оквиру семинара Центра за физику чврстог стања и нове материјале, у читаоници Института за физику „Др Драган Поповић“ у петак, 19. априла 2019. године, у 13:00 часова др Чедомир Петровић, Брукхејвен национала лабораторија, САД, одржаће предавање под насловом:

„Superconductivity and Magnetism in 2D Materials“

Сажетак:

Superconductivity and charge-density-wave (CDW) are traditionally
viewed as Fermi surface instabilities due to electron-phonon
coupling whereas arguments have been made both for their
cooperation and competition [1-4]. In this talk I will discuss
emergence of superconductivity in the absence of magnetism from the
standpoint of disorder in doped two-dimensional (2D) CDW conductors
ZrTe3 and 2H-TaSe2-xSx [5- 10]. In the second part of my
talk I will briefly discuss magnetic critical phenomena and effects
of size reduction in CrI3 and other 2D materials of current interest
[11-12].

References: [1] G. Grüner, Rev. Mod. Phys. 60, 1129 (1988), [2] T. Kiss
et al., Nature Physics 3, 720 (2007), [3] S. V. Borisenkoet al., Phys.
Rev. Lett. 102, 166402 (2009). [4] E. Fradkin et al., Rev. Mod. Phys.
87, 457 (2015), [5] Xiangde Zhu et al., Phys. Rev. Lett. 106, 246404
(2011), [6] Hechang Lei et al., Europhys. Lett. 95, 17001 (2011), [7]
Xiangde Zhu et al., Sci. Rep. 6, 26974 (2016), [8] Lijun Li et al.,
NPJ Quantum Materials 2, 11 (2017). [9] M. Hoesch et al.,
arXiv:1712.03379, [10] A. M. Ganose et al., arXiv:1712.06551, [11] Yu
Liu et al., Phys. Rev. B 97, 014420 (2018), [12] Yu Liu et al.,
submitted (2019).

У оквиру семинара посвећеног историји науке и теорији сазнања позивамо вас на предавање:

„Подељено ЈА: психолошки, математичко-постмодерни и квантно-механички
аспект“

које ће у уторак, 23. априла 2019. у 13 часова у читаоници библиотеке „Драган Поповић“ одржати др Владимир Ђоковић (Институт за нуклеарне науке „Винча“, Београд).

У оквиру традиционог колоквијума Института за физику, у среду, 17. априла 2019. у 12 часова у сали „Звонко Марић“ предавање под насловом

Machine Learning and Condensed Matter: What can we learn?

ће одржати проф. др Никола Рењо (Laboratoire de Physique, Ecole Normale Superieure – CNRS, Paris, France).

САЖЕТАК:

Relying on the advance of computing power, algorithms and large databases, machine learning (ML) has become a paradigmatic change in many areas. The versatility of the techniques and the success of ML have triggered a large interest in this approach applied to condensed matter. Obviously, it can be used as an advanced data analysis method for experimental results. In this talk, we will focus on ML in more theoretical contexts. Through a few examples, we will unveil its potential applications. We will discuss how it can discriminate between different phases in numerical simulations and how it can be used to encode many-body quantum states in an efficient manner.

У оквиру СЦЛ семинара Центра за изучавање комплексних система, у четвртак 18. априла 2019. у 14:00 у читаоници Института за физику „Др Драган Поповић“, Миљан Дашић (СЦЛ, Институт за физику у Београду) у оквиру предавања

Modeling the behavior of confined dipolar configurations and ionic liquids

претставиће изабране резултате из своје докторске дисертације.

САЖЕТАК:

Self-assembly of hard spheres with permanent dipole moment under cylindrical confinement, (dipolar helices composed of dipolar hard spheres) has been investigated [1]. An approach for studying mesoscopic phenomena related to the lubrication with ionic liquids based on coarse-grained molecular dynamics simulations has been developed [2, 3, 4]. Two generic models of ionic liquid, i.e., salt model (SM) [2, 3] and tailed model (TM) [4] have been implemented. The behavior of both bulk and confined ionic liquids has been carefully studied under static and dynamic conditions. The similarity of dipolar configurations and ionic liquids comes from the fact that their structure and behavior are governed by long-range interactions: dipole-dipole interaction (which is in addition anisotropic) and Coulombic interaction. Lekner method for summing the dipole-dipole interactions of 1D periodic structures has been applied for studying dipolar configurations, while MSM (multi-level summation) method for handling Coulombic interactions has been applied in the study of ionic liquids. A clear emergence of ordered structures (geometrically regular dipolar configurations and alternating ionic liquid layers) is a clear consequence of long-range interactions.

References:
[1] I. Stanković, M. Dašić and R. Messina, “Structure and cohesive energy of dipolar helices”, Soft Matter 12, 3056 (2016)
[2] K. Gkagkas, V. Ponnuchamy, M. Dašić and I. Stanković, “Molecular dynamics investigation of a model ionic liquid lubricant for automotive applications”, Tribology International 113, 83 (2017)
[3] M. Dašić, I. Stanković and K. Gkagkas, “Influence of confinement on flow and lubrication properties of a salt model ionic liquid investigated with molecular dynamics”, The European Physical Journal E 41, 130 (2018)
[4] M. Dašić, I. Stanković and K. Gkagkas, “Molecular dynamics investigation of the influence of the shape of the cation on the structure and lubrication properties of ionic liquids”, Physical Chemistry Chemical Physics 21, 4375 (2019)

У оквиру семинара Центра за фотонику, у среду, 17. априла у 13 часова у читаоници библиотеке „Др Драган Поповић“ предавање под насловом

Bioanalytics using plasmonic nanostructures

одржаће Волфганг Фрицше (Leibniz Institute of Photonic Technology (IPHT))

САЖЕТАК:

Novel requirements for bioanalytical methods emerge due to trends such as personalized medicine or pathogen monitoring in environment and food. Here, innovative tools for diagnostics are needed, to be used outside of dedicated laboratories and with less qualified personnel, at minimal costs. Plasmonic nanostructures promise to provide sensing capabilities with the potential for ultrasensitive and robust assays in a high parallelization, and without the need for marker. Upon binding of molecules, the localized surface plasmon resonance (LSPR) of these structure is changed, and can be used as sensoric readout [1]. This is possible even on a single nanostructure level, using optical darkfield detection introduced more than 100 years ago [2], as demonstrated for DNA detection [3]. In contrast to SPR, LSPR senses only in a very thin layer (on the scale of the particle diameter), resulting in an efficient background suppression [4].
In order to multiplex this approach, an imaging spectrometer based on a Michelson interferometer has been developed, able to readout a whole array of sensors in one step [5]. On the sensor side, microarrays of gold nanoparticle spots were fabricated using spotting of pre-synthesized gold nanoparticles [6].  Such chemically synthesized particles allow for a cost-efficient generation of highly crystalline particles as nanosensors; by using microfluidic approaches, a high quality and reproducibility can be achieved [7]. The functionalization of the various particle spots is realized by spotting thiolized DNA onto each spot separately. Using this approach, a multiplex DNA-based detection of fungal pathogens involved in sepsis was possible [8].
Besides sensing, individual plasmonic nanostructures can be also used to optically manipulate biomolecular structures such as DNA. Attached particles can be used for local destruction [9] or cutting as well as coupling of energy into (and guiding along) the molecular structure upon laser irradiation [10]. The resonance wavelength of these particles can not only manipulated by their inherent properties (material, geometry) or their surrounding, but also by coupling with adjacent metal films due to interferometric effects [11] or gap modes. This effects is also usable for a novel sensing approach by inserting a flow-through channel between particle and the metal film mirror, analyte particle moving through the channel will change the refractive index in the space between particle and mirror and thereby change the LSP resonance observed.

[1]    A. Csaki, T. Schneider, J. Wirth, N. Jahr, A. Steinbrück, O. Stranik, F. Garwe, R. Müller and W. Fritzsche, Philosophical Transactions A 369, 3483-3496 (2011).
[2]    T. Mappes, N. Jahr, A. Csaki, N. Vogler, J. Popp, W. Fritzsche. Angew Chem Int Ed 51, 11208-11212 (2012)
[3]    T. Schneider, N. Jahr, A. Csaki, O. Stranik and W. Fritzsche, J Nanopart Res 15, 1531 (2013)
[4]    J. Jatschka, A. Dathe, A. Csaki, W. Fritzsche, O. Stranik. Sensing and BioSensing Research 7, 62-70 (2016)
[5]    D. Zopf, J. Jatschka, A. Dathe, N. Jahr, W. Fritzsche, O. Stranik. Biosensors and Bioelectronics 81, 287-293 (2016)
[6]    A. Pittner, S. Wendt, D. Zopf, A. Dathe, N. Grosse, A. Csaki, W. Fritzsche, O. Stranik. Analytical and Bioanalytical Chemistry (2019) accepted
[7]     Thiele M, Soh J Z E, Knauer A, Malsch D, Stranik O, Müller R, Csáki A, Henkel T, Köhler J M and Fritzsche W 2016 Chemical Engineering Journal 288 432–40
[8]    D. Zopf, A. Pittner, A. Dathe, N. Grosse, K. Arstila, J. Toppari, W. Schott, D. Dontsov, G. Uhlrich, W. Fritzsche, O. Stranik. ACS Sensors (2019) in revision
[9]    A. Csaki, F. Garwe, A. Steinbrück, G. Maubach, G. Festag, A. Weise, I. Riemann, K. König and W. Fritzsche, Nano Letters 7 (2), 247-253 (2007).
[10]    J. Wirth, F. Garwe, G. Haehnel, A. Csaki, N. Jahr, O. Stranik, W. Paa and W. Fritzsche, Nano Letters 11 (4), 1505-1511 (2011).;  J. Toppari, J. Wirth, F. Garwe, O. Stranik, A. Csaki, J. Bergmann, W. Paa, W. Fritzsche, ACS Nano 7, 1291-1298  (2013); J. Wirth, F. Garwe, J. Bergmann, W. Paa, A. Csaki, O. Stranik, W. Fritzsche. Nano Letters 14, 570-577 (2014)
[11]    J. Wirth, F. Garwe, R. Mayer, A. Csaki, O. Stranik, W. Fritzsche: Nano Letters 14, 3809-3816 (2014)