The seminars are regularly held on Wednesday, 11:00-12:00 in S11-02-07 unless otherwise announced.
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|Date / Speaker||Title / Abstract|
|Date / Speaker||Title / Abstract|
|Date / Speaker||Title / Abstract|
|29 Mar 2017
Frank Watt (NUS Centre for Ion Beam Applications)
|Fast protons: from super-resolution microscopy to cancer therapy|
The Centre for Ion Beam Applications, Dept of Physics, is an interdisciplinary research centre which was set up around 15 years ago to investigate the potential of fast ions [ie million volt proton and helium ions] in a wide range of disciplines. CIBA has pioneered many unique technologies since its inception, including proton beam writing, silicon micromachining, and fast ion beam microscopy [which is being used for cell imaging at super-resolutions - resolutions better than the diffraction limit of light]. Singapore is constructing a new National Cancer Centre [NCCS] building [costing around 55 0.75 billion], situated in the Outram Park Campus [56H]. The new Centre will include a state-of-the—art proton therapy facility utilising fast protons for cancer treatment. It is well known that proton beam therapy can target tumours with greater accuracy and with less collateral damage to surrounding healthy tissue compared with traditional radiation therapy using X-rays. At the cellular level however, the localised action of fast protons inside the cell nucleus is not well understood. This talk will describe the development and underlying principles of fast ion microscopy in CIBA. the basics of proton beam therapy, and show how these two programmes can be linked via a recently funded new research programme into single cell proton radiobiology to be carried out at CIBA.
|22 Mar 2017
Sarah Demers (Yale University, USA)
|An update from CERN's Energy Frontier|
Since discovering the Higgs boson in 2012, the ATLAS and CMS Experiments have been hard at work characterizing this particle and searching for other evidence of physics beyond the Standard Model. CERN's Large Hadron Collider delivered a substantial dataset in 2016, and we anticipate even more integrated luminosity in 2017. In this talk I will describe where we stand in terms of Higgs boson measurements at ATLAS, and our strategy for searches for new physics.
|1 Mar 2017
Peter Hänggi (University of Augsburg, Germany)
|(Quantum) Thermodynamics at strong coupling and its implications for Stochastic Thermodynamics|
The case of strong system-environment coupling plays an increasingly important role when it comes to describe systems of small size which are in contact with an environment. The commonly known textbook situation refers solely to a weak coupling situation for which the equilibrium state of the system is described by a Gibbs state. This situation changes drastically, however, when strong coupling is at work; then, the interaction energy can be of the order of the (sub)-system energy of interest . Let us consider first an overall thermal equilibrium of a total setup composed of a system Hamiltonian HS, coupling Hamiltonian Hint and a bath Hamiltonian HB.
|15 Feb 2017
Loren Alegria (Princeton University, USA)
|Topological Insulator Nanostructures and Devices |
2D materials afford a natural solution to interfacial issues encountered in scaling electronic devices. Among 2D materials, the layered topological insulators have extreme spin-orbit coupling and a unique quintuple layer structure, enabling the creation of unprecedented nanostructures and spintronic devices. We present measurements of topological insulator nanostructures, focusing on high quality quantum wires, heterostructures between topological insulators and ferromagnetic insulators, and self-assembled topological insulator nanotubes.
|8 Feb 2017
Peng Weng Kung (Nanyang Technological University)
|Rapid and Label-free Magnetic Resonance based Molecular Phenotyping of Oxidative Stress of Diabetes Mellitus |
Diabetes mellitus (DM) is one of the fastest growing health burdens that is projected to affect 592 million people worldwide by 2035 . In this talk, a new paradigm of molecular phenotyping using the fundamental of spin physics for clinical diabetes care and management, will be introduced. Specifically, we aim to establish high throughput oxidative stress and metabolic phenotyping platform for DM. We have recently shown that various pathological states (e.g., oxidative stress of diabetes mellitus , malaria infection [3,4], and blood oxidation/oxygenation level [5,6]) can be rapidly captured (< 5 minutes) by mapping out the redox properties of blood (< 10 µL) using inexpensive, home-built, microscale magnetic resonance (MR) technology. A range of microscale MR technology (relaxometry, spectroscopy, imaging) developed in the pipeline will be used as the platform in translating a new class of functional biomarkers for DM medical research and clinical practices. In addition, the speaker will discuss briefly the newly developed ultrafast multidimensional relaxographic imaging  for next generation of rapid and label-free molecular phenotyping. We demonstrate its clinical utilities in sub-phenotyping the hemoglobinopathies (e.g., thalassemia), assessment of glucose toxicity in pancreatic islets and sub-stratification of endometriosis disease.
|25 Jan 2017
Siddarth Saxena (University of Cambridge, UK)
|Tuneable Spin and Charge Phenomena|
Materials tuned to the neighbourhood of a zero temperature phase transition often show the emergence of novel quantum phenomena. Much of the effort to study these new emergent effects, like the breakdown of the conventional Fermi-liquid theory in metals has been focused in narrow band electronic systems. Ferroelectric crystals provide a very different type of quantum criticality that arises purely from the crystalline lattice. In many cases the ferroelectric phase can be tuned to absolute zero using hydrostatic pressure. Close to such a zero temperature phase transition, the dielectric constant and other quantities change into radically unconventional forms due to the fluctuations experienced in this region. The simplest ferroelectrics may form a text-book paradigm of quantum criticality in the solid-state where there are no complicating effects of electron damping of the quantum charge fluctuations. We present low temperature high precision data demonstrating these effects in pure single crystals of SrTiO3 and KTaO3. We outline a model for describing the physics of ferroelectrics close to quantum criticality and highlight the expected 1/T2 dependence of the dielectric constant measured over a wide temperature range at low temperatures. In the neighbourhood of the quantum critical point we report the emergence of a small frequency independent peak in the dielectric constant at approximately 2K in SrTiO3 and 3K in KTaO3. Looking to the future, we imagine that quantum paraelectric fluctuations may lead to new low temperature states and mediate novel interactions in multi-ferroic systems (e.g. EuTiO3) and ferroelectric crystals supporting itinerant electrons.
|18 Jan 2017
Won Jong Yoo (Sungkyunkwan University, Korea)
|Carrier Transport at the interface of 2-dimensional materials |
Two dimensional (2D) materials are being investigated very intensively, with some of them holding great promise as semiconducting materials for future low power nano-electronics, as they present a range of achievable bandgaps and ultra-thin body with efficient electrostatic control. These properties, combined with mechanical flexibility, enable 2D materials to be very promising candidates that can meet major requirements for electronic and photonic devices operated in emerging future mobile and IoT environment.
|11 Jan 2017
Adolfo del Campo (University of Massachusetts, USA)
|Engineering Quantum Thermal Machines |
Quantum thermodynamics has the potential to impact energy science. Yet, the identification of scenarios characterized by a quantum supremacy, unmatched by the classical counterpart, remains challenging. In this talk I shall review recent advances in the engineering and optimization of quantum thermal machines. I will show that nonadiabatic many-particle effects can give rise to quantum supremacy in finite-time thermodynamics. Further, quantum heat engines can be operated at maximum efficiency and arbitrarily high output power by making use of shortcuts to adiabaticity. A thermodynamic cost of these shortcuts will be elucidated by analyzing the full work distribution function and introducing a novel kind of work-energy uncertainty relation. I shall close by discussing the identification of scenarios with a quantum-enhanced performance in thermal machines run over many cycles.