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Day | Week | Month | Year | Upcoming

Sunday, 01 January 2017 - Sunday, 31 December 2017

< 2016 | 2018 >

Abstract: In any approach to quantum gravity, it is crucial to search for observational effects. In my talk, I discuss how quantum-gravitational contributions to the anisotropy spectrum of the cosmic microwave background arise in the framework of quantum geometrodynamics (Wheeler-DeWitt equation). A scenario of slow-roll inflation is assumed. From the present non-observation of these contributions, one finds a constraint on the Hubble parameter of inflation. I end with a brief comparison of this approach with loop quantum cosmology.
Event Time
10:00 - 11:00
Venue
Physics C36
Speaker
Prof. Claus Kiefer, University of Cologne
There have been some breakthroughs in the last decade in the long-standing problem of predicting the structure of materials at the atomic scale. This is a hard problem in global optimization. Methods such as genetic algorithms, random structure search, and particle-swarm optimization have been applied to clusters and crystals with some success. In this talk, I will discuss recent work within my group on lower dimensional structures, include surface reconstructions of bulk materials (e.g. Si(111), and edge reconstructions of nano ribbons (e.g. MoS2). I will also discuss a current project on predicting the magnetic structure of materials.
Event Time
3pm-4pm
Venue
C36 Physics
Speaker
Prof Matt Probert, University of York
Short gamma-ray bursts are believed to be produced by ultra-relativistic jets launched from the merger of neutron stars (NSNS) or a black-hole and a neutron star (BHNS). A short (<2s) flash of gamma-rays, from internal shocks, is followed by a multi-band afterglow from external shocks as the jet decelerates in the ambient medium. Observations of the afterglow are currently triggered by the prompt gamma-rays. For jets with a bulk Lorentz factor <30 the prompt gamma-rays would be suppressed, resulting in an orphan afterglow as the jet decelerates. If low-Lorentz factors dominate the distribution of merger jets, then gravitational wave triggers from NSNS(BHNS) mergers will reveal a hidden population of failed short gamma-ray bursts. The electromagnetic counterparts to gravitational wave detected NSNS(BHNS) mergers can be used to determine the Lorentz-factor distribution, opening-angle, and structure of such jets
Event Time
1500 - 1600hrs
Venue
C36 Physics
Speaker
Gavin Lamb (Liverpool John Moores University
Hear first hand about the experience of PhD students in Physics and talk to members of different research groups. Refreshments will be provided and everyone is welcome!
Event Time
13:00 - 14:00
Venue
LUMS LT10 (B floor)
While the ATLAS Experiment at the Large Hadron Collider has not even collected 10% of its design integrated luminosity, upgrades to both the LHC and ATLAS are well underway to extend their physics reach thanks to more statistics, with installation envisaged for about 2025.
Event Time
13:45 - 14:45
Venue
Physics C36
Speaker
Dr. Daniel Muenstermann, Lancaster University
The study of atmospheric neutrinos has revolutionised the field of neutrino physics with the discovery of neutrino oscillations in 1998. The importance of this discovery was recognized with the Nobel Prize in 2015, awarded to Kajita and McDonald. Almost 20 years after this breakthrough, many questions still loom over neutrino oscillations, and the KM3NeT- ORCA experiment is going after one of the most important: What is the the ordering of neutrino masses? As part of a new generation of atmospheric neutrino detectors, ORCA is being built in the Mediterranean Sea and will instrument a 6 Mton volume of seawater with 64000 PMTs. This large mass and dense instrumentation will enable ORCA to collect high statistics atmospheric neutrino data in the 3 - 7 GeV energy range, where resonant neutrino flavour transitions are expected to occur. In this seminar, I will explain how these resonant transitions arise from neutrino interactions with the matter through which they travel inside the earth, and how this phenomenon can be used to infer the ordering of the neutrino masses. I will also comment on how these same effects can be used to search for new physics beyond the Standard Model and may even allow us to directly measure the chemical composition of the earth for the first time.
Event Time
13:45 - 15:00
Venue
Physics C36
Speaker
Dr. Joao Coelho, APC Paris
Solar cycle variations in solar radiation create notable density changes in the Martian ionosphere. In addition to this long-term variability, there are numerous short-term and non-recurrent solar events that hit Mars which need to be considered, such as Interplanetary Coronal Mass Ejections (ICMEs), Co-Rotating Interaction Regions (CIRs), solar flares, or solar wind high speed streams. The response of the Martian plasma system to each of these events is often unusual, especially at different phases of the solar cycle. Moreover, there are other phenomena such as comet flybys that can notably affect the ionosphere of Mars. An example is the recent Siding-Spring comet encounter with Mars. The work is based on multi-spacecraft measurements, such as Mars Express, MAVEN, Mars Odyssey and MSL and with the help of empirical and numerical models. It is also supported by simulations using the solar wind WSA-ENLIL+Cone model and data from Earth orbit.
Event Time
1400-1500
Venue
Bowland North Seminar Room 6
Speaker
Dr. Beatriz Sanchez-Cano, University of Leicester
Abstract: Silicon complementary metal oxide semiconductor (CMOS) technology has driven the success of the semiconductor industry in the last few decades. The classical computational power has increased exponentially but this progress is bound to reach its fundamental limits in the next years. We are now starting to see that CMOS technology itself can offer an alternative to overcome its classical fundamental limits, not in terms of continued miniaturization but in terms of a different computing paradigm: quantum computation. In this talk, I will present a series of results on fully depleted silicon-on- insulator (FD-SOI) transistors at mili-Kelvin temperatures that demonstrate this technology can provide a platform for high-integration qubit architectures.
Event Time
3pm-4pm
Venue
C36 Physics
Speaker
Dr Fernando Gonzalez-Zalba, Hitachi Cambridge Laboratory
Classical scale invariance was applied to inflationary model building already from the very first papers. Recently the use of dynamically induced inflaton potentials à la Coleman-Weinberg became again fashionable. In the light of this, we study different applications of classical scale invariance to inflation. Depending on whether classical scale invariance is a property of the full action or just of the scalar potential, we consider three different realizations of Coleman-Weinberg inflation in presence of a non-minimal coupling of the inflaton to gravity. For each realization, we present the most relevant inflationary predictions and distinctive features.
Event Time
2pm-3pm
Venue
C36 Physics
Speaker
Dr. Antonio Racioppi (National Institute of Chemical Physics and Biophysics, Tallinn)
Abstract to follow
Event Time
1500 - 1600hrs
Venue
C36 Physics
Speaker
Mark Sullivan (University of Southampton)
The existence of a light sterile neutrino species has been postulated to explain certain anomalies present in some neutrino oscillation experiments, with limits usually provided by other oscillation searches. However, constraints can also come from double-beta decay experiments, and I will show how the limits from the neutrinoless double-beta decay searches can constrain the parameter space of sterile neutrinos. Further limits on the sterile neutrino can also be provided by astronomical observation, from measurements of the Cosmic Microwave Background by the Planck experiment, and I will show how these limits can be translated into the parameter space used in neutrino oscillation searches.
Event Time
13:45 - 14:45
Venue
Physics C36
Speaker
Dr Pawel Guzowski, Manchester
NaChBac was the first discovered bacterial sodium voltage-dependent channel, yet computational studies are still limited due to the lack of a crystal structure. In this work a pore-only construct built using the NaVMs template was investigated using unbiased Molecular Dynamics and Metadynamics. The Potential of Mean Force (PMF) from the unbiased run features four minima, three of which correspond to sites IN, CEN and HFS discovered in NavAb. During the run the Selectivity Filter (SF) is spontaneously occupied by two ions and frequent access of a third one is often observed. Metadynamics simulations biasing one and two ions, show an energy barrier in the SF that prevents single-ion permeation. An analysis of the permeation mechanism was performed both computing minimum energy paths in the axial-axial PMF and through a combination of Markov State modeling and Transition Path Theory. Both approaches reveal a knock-on mechanism involving at least two, but possibly three ions. An intriguing feature of NaChBac is that, despite being a sodium channel, the sequence of its Selectivity Filter is similar to that of Calcium ions. The molecular basis of Na/Ca selectivity of this channel is thus not clear. In a long unbiased simulation, a single Calcium ion access the SF where it remains stuck until the end of the calculation. We identify two reasons for Ca2+ inability to cross the SF: its higher free energy of binding with respect to Na+ and the electrostatic repulsion that the internal Ca2+ exerts on a potentially incoming second calcium, thus preventing a knock-on mechanism. Finally, through metadynamics simulations we show that the resident calcium ion can not prevent a Na+ ion from crossing the filter so that there is no anomalous mole fraction effect (AMFE) in agreement with experimental data.
Event Time
3pm-4pm
Venue
C36 Physics
Speaker
Dr. Carlo Guardiani, University of Warwick
With the discovery of the Higgs boson, the Standard Model (SM) is complete. Yet the SM is itself an incomplete description of nature. One strategy to go beyond this model is to search for new processes through SM measurements. An effective field theory (EFT) describes the impact of these processes as small deviations from the SM in orders of the inverse scale of new physics. A complete fit of the EFT operator coefficients provides a generalised probe for new physics. I discuss the potential for such a fit, focusing on the contributions from precision Higgs and electroweak measurements.
Event Time
13:45 - 14:45
Venue
Physics C36
Speaker
Dr Chris Hays, Oxford
Super-Soft X-ray Sources (SSS) are a small class of X-ray sources characterised by a blackbody-like spectrum of effective temperature 30-100 eV (several 10^5 K) and luminosities above 10^36 erg/s. Owing to their softness, galactic SSS are more difficult to observe and interpret because of high galactic extinction and uncertain distances, respectively. While a small number of permanent SSS are known since the 80s, novae have been predicted to pass through a phase of SSS emission that has indeed been observed with, e.g., ROSAT, BeppoSAX, or ASCA. Attempts of spectral modeling of nova SSS spectra ranged from blackbody fits to most refined local thermodynamic equilibrium (LTE) and non-LTE atmosphere modeling, but the low resolution of CCD spectra allows no unique constraint of spectral parameters of complex models. The X-ray grating spectrometers on board XMM-Newton and Chandra allow much more detailed analysis of SSS spectra and, as always in nature, the truth is much more complicated than believed. I will first present historic observations and attempts of interpretation, and then show the grating spectra with the details. A large variety in grating spectra of canonical SSS spectra and those of novae emerged, and I will show approaches how to find trends and to explain some commonalities. Spectral modeling is currently not possible, but I will present and discuss some approaches
Event Time
1100 - 1200hrs
Venue
Bowland North SR 23
Speaker
Jan-Uwe Ness (European Space Astronomy Centre, Madrid)
LHC measurements and searches are usually conducted with a particular theory model in mind, but can also have unexpected implications for alternative scenarios. Especially in the absence so far of smoking gun signals of new physics at the LHC, reinterpreting combinations of many "preserved" data analyses in this way, applied to more general models of beyond-SM physics has become a big business. I will show uses of the Rivet & Professor MC toolkits for reinterpretation of electroweak, top quark, and BSM search data in this way, particularly in first results from the TopFitter, Contur, and Gambit fitting groups, and how these studies can also inform future experimental measurements.
Event Time
13:45 - 14:45
Venue
Physics C36
Speaker
Andy Buckley, Glasgow
We have measured the mobility and limiting terminal velocity of electron bubbles sliding along vortex lines in superfluid 4He for a broad range of temperatures (0.1 - 1 K). This allows dissipative processes at small length scales to be probed, which can include drag exerted by an excess density of excitations in the vicinity of the vortex core; the scattering and generation of Kelvin waves and solitons; condensation of 3He impurity atoms onto vortex cores. We have also used this technique to probe the dynamics of agitated vortex arrays and the corresponding timescales for relaxation back towards a rectilinear array, providing new insight into the decay of quantum turbulence at short length scales.
Event Time
3pm-4pm
Venue
C36 Physics
Speaker
Dr Paul Walmsley, University of Manchester
Massive stars formed in atomic hydrogen reservoirs
Event Time
1130 - 1230hrs
Venue
C36 Physics
Speaker
Michal Michalowski (University of Edinburgh)
Neutrino oscillation has been clearly established via the study of solar, atmospheric, reactor and beam neutrinos.
Event Time
13:45 - 14:45
Venue
Physics C36
Speaker
Dr Jaime Dawson, APC Paris
Observational Astrophysics Seminar - The star-forming ISM: bottom-up versus top-down approaches
Event Time
1330 - 1430hrs
Venue
C36 Physics
Speaker
Paul Clark (Cardiff University)
Reconfiguring the Fields of Astrophysical Objects: Magnetic Reconnection, Parallel Electric FIelds, and Turbulence
Event Time
3pm-4pm
Venue
Marcus Merriman LT
Speaker
Prof. Bob Ergun, University of Colorado
I will review our recent progress in the generation of kHz relativistic electron beams driven by single-cycle laser pulses. This new source, providing 5 MeV electrons with few femtosecond duration has great potential for studying ultrafast structural dynamics via ultrafast electron diffraction (UED). I will also show recent UED results showing intriguing lattice dynamics in single crystal Silicon.
Event Time
3pm-4pm
Venue
C36 Physics
Speaker
Prof. Jérôme Faure, ENSTA ParisTech
Electroweak production measurements at the LHCb experiment. LHCb is able to make important contributions in areas of research beyond LHCb's original remit in beauty and charm physics.
Event Time
13:45 - 14:45
Venue
Physics C36
Speaker
Dr Will Barter, Manchester
Solid-state quantum emitters are required for quantum information protocols relying on the storage, manipulation, and transmission of the information encoded in single photons through optical cavities and waveguides. Semiconductor quantum dots are particularly promising quantum light sources that can allow both the investigation of fundamental physics phenomena on a chip and quantum technology applications [1]. I will discuss the implementation of quantum dot nanostructures to create simultaneously bright and pure, on-demand, single-photon sources in engineered nanophotonic devices in gallium arsenide [2] and hybrid silicon/III-V materials [3]. I will present different photonic geometries for controlling light propagation, brightness and spontaneous emission rate, based on circular grating and ring cavities. Finally, I will focus on the comparison between highly engineered structures and disordered photonic crystal waveguides, showing efficient light confinement and optical sensing on a silicon nitride platform in the visible range of wavelengths [4]. References: [1] O. Gozzano, G.S. Solomon, Toward optical quantum information processing with quantum dots coupled to microstructures, Journal of the Optical Society of America B 33, C160 (2016) [2] L. Sapienza, M. Davanco, A. Badolato, K. Srinivasan, Nanoscale optical positioning of single quantum dots for bright and pure single-photon emission, Nature Communications 6, 7833 (2015). [3] M. Davanco, J. Liu, L. Sapienza, C.-Z. Zhang, J.V. De Miranda Cardoso, V. Verma, R. Mirin, S. W. Nam, L. Liu, K. Srinivasan, A heterogeneous III-V/silicon integration platform for on-chip quantum photonic circuits with single quantum dot devices, arxiv.org/abs/1611.07654 (2016). [4] T. Crane, O.J. Trojak, L. Sapienza, Anderson localisation of visible light on a nanophotonic chip, arxiv.org/abs/1605.08614 (2016).
Event Time
3pm-4pm
Venue
C36 Physics
Speaker
Dr Luca Sapienza, University of Southampton
Abstract: I will describe the ever growing zoo of objects [globular clusters, ultra-compact dwarf galaxies, compact ellipticals etc.] with properties intermediate between star clusters and true galaxies and discuss the insights they can provide into the formation and evolution of galaxies.
Event Time
1500 - 1600hrs
Venue
C36 Physics
Speaker
Mark Norris (UCLan)
Two members of the Physics Dept staff, Dr Louise Willingale and Dr Licia Ray, will be speaking about their careers to date. This event will provide a fascinating insight into the life of the professional scientist, and how to get started in the field, and will be a must-attend for anyone considering a career of this type. Join us for this great opportunity to meet other members of the Department and discuss career paths. Refreshments provided, everyone is welcome! For more info contact Sarah Badman
Event Time
13:00 - 14:00
Venue
Bowland North SR6
Speaker
Dr Louise Willingale and Dr Licia Ray, Lancaster University
Many superconducting micro- and nano-electronic devices operating at low temperatures suffer from the presence of non-equilibrium quasiparticles. The number of these quasiparticles increases rapidly with the increase in the operation frequencies above the threshold determined by the relaxation rate.
Event Time
3pm-4pm
Venue
C36 Physics
Speaker
Dr. Ivan Khaimovich, Max Planck Institute for Physics of Complex Systems Condensed Matter
Join us to meet Physics researchers and talk about whatever you're working on or would like to work on in the future, including summer/undergraduate research projects. Refreshments will be provided and everyone is welcome!
Event Time
13:00 - 14:00
Venue
C36, Physics
Water Cherenkov detectors have been a mainstay of neutrino physics since the 1970s. Over nearly four decades, they have discovered neutrino oscillations, solved the solar neutrino problem, and made the first observation of neutrinos from beyond our galaxy. Looking forward, the capabilities of this technology can be enhanced by loading the water with gadolinium, enabling neutron detection in the aftermath of a neutrino interaction. Following a feasibility demonstration with the EGADS prototype, several experiment are planning to employ this technique in the next few years. During this presentation, I will discuss two such experiments that will harness Gd-loading to achieve very different goals. The Accelerator Neutrino-Nucleus Interaction Experiment (ANNIE) will sit in the Fermilab Booster Neutrino Beam and study neutron yield in neutrino interactions. Meanwhile, the WATer CHerenkov Monitor for Anti-Neutrinos (WATCHMAN) will demonstrate the ability of such detectors to do remote monitoring of reactors for the purpose of nuclear non-proliferation.
Event Time
13:45 - 14:45
Venue
Physics C36
Speaker
Matthew Malek, Sheffield
The shot noise is originated from the granularity of the particles. However, in tunnelling devices with negligible level spacing, the noise in tunnelling current induced by particle-environment interaction is classified as thermal rather than shot noise. We argue that for systems with the level spacing much greater than the thermal energy, the particle interacting with the environment can induce a new class of shot noise.
Event Time
3pm-4pm
Venue
C36 Physics
Speaker
Dr. Chii-Dong Chen, Institute of Physics, Academia Sinica, Taipei, Taiwan
Part of the Earth's magnetic field, known as “open flux”, is directly connected to the interplanetary magnetic field. Whilst the interplanetary magnetic field is responsible for the opening of flux, the closing of flux is unpredictable and poorly understood. We can track increases and decreases in open flux using pictures of the aurora from the Imager for Magnetopause-to-Aurora Global Exploration (IMAGE) satellite. Substorms, where explosive brightenings of the nightside aurora are observed alongside rapid decreases in open flux, are thought to be one of the most fundamental modes of magnetospheric response. Sometimes, substorms can lead to a steady magnetospheric reconnection event, where day- and nightside reconnection rates are balanced. When the driving of the Earth's magnetosphere is most extreme, quasi-periodic unloading events, known as sawtooth events, can be observed. In this talk I explore these magnetospheric modes and solar wind driving in the context of the expanding and contracting polar cap paradigm.
Event Time
1400-1500
Venue
C36 Physics
Speaker
Dr. Maria-Theresia Walach (Lancaster University)
The last decade has seen remarkable advances in the astronomy of the bulge of our own Milky Way Galaxy, with models finally able to naturally explain sets of observational properties that until recently appeared to be mutually contradictory. At the same time, an explosion of observational activity is opening new windows on the properties of the populations that make up the bulge. I will present a selection of results from narrow-deep observations from space-based observatories (most prominently the Hubble Space Telescope), which are both shedding new light on the multiple intrinsic populations in the bulge, and will be important calibrators for planned surveys. If time permits, I will introduce some of the exciting new investigations permitted by the new generation of ground-based "wide-fast-deep" surveys, particularly using DECam and the Large Synoptic Survey Telescope (LSST).
Event Time
1230 - 1330hrs
Venue
County Main SR 4
Speaker
Will Clarkson (University of Michigan-Dearborn)
Exploring the frontier between the quantum and the classical world is of fundamental interest. In quantum optomechanics, we tackle this problem by using cavity photons interacting many times with a mechanical resonator to detect its motion precisely. At room temperature, we observe a classical motion, but at low temperature we can detect quantum effects. This technique is a promising tool as it allows probing either side of the classical-quantum frontier. Yet, most fabricated resonators have strong limitations due to material losses, which prevents testing theoretical predictions. The focus of my research programme is to develop a new platform, to exploit superfluid helium as a mechanical element for quantum optomechanics. Supefluid helium is a very exotic material showing vanishing losses at low temperature. To build our mechanical resonator, we will confine superfluid helium into a nanoscale acoustic cavity. We will detect its motion via a parametrically coupled superconducting microwave cavity embedded inside the acoustic cavity. This unique architecture offers unprecedented performances for an optomechanical system and high flexibility in design. I will present our last results in the development of superfluid acoustic resonators [Souris et al. Phys. Rev. Applied 7, 044008 (2017)], and our designs for superfluid optomechanics within the nanofluidics environment.
Event Time
3pm-4pm
Venue
C36 Physics
Speaker
Dr. Xavier Rojas, Royal Holloway, University of London
UCL have operated Fabry-Perot Interferometers in Arctic Scandinavia since 1980: at a polar cap site – Svalbard; and 2 auroral oval sites – Kiruna and Sodankylä.
Event Time
2pm-3pm
Venue
C36 Physics
Speaker
Amy Ronksley and Anasuya Aruliah (UCL)
The study of out-of-equilibrium thermodynamics has received a significant thrust thanks to the experimental advances in the control and manipulation of microscopic systems. Work, an ubiquitous concept in traditional thermodynamics, assumes in this context the role of a stochastic variable whose uctuations can be ingeniously related to equilibrium properties, as is the case of the celebrated Jarzynski equality [1]. This formalism can be extended to quantum mechanics where work is measured through repeated measurements of the system energy. The current challenges in quantum thermodynamics include the design of heat engines and refrigerators that exploit the quantum coherence of the working substance. In this seminar, I will revise these concepts and discuss feasible experimental schemes to directly measure work in cold atomic setups. I will show that the interaction between atoms and the light polarisation of a probe laser, as in atomic ensembles experiments, allows us to measure work uctuations through a homodyne measurement of the output light [2]. A second scheme allows one to measure the work done on an atomic BEC in a double well potential when the atomic self-interaction is varied. I will discuss strategies based on optimal control techniques to reduce the irreversible work production [3].
Event Time
3pm-4pm
Venue
C36 Physics
Speaker
Dr. Gabriele De Chiara, Centre for Theoretical Atomic, Molecular and Optical Physics, Queen's University Belfast
Abstract: Auroral hot spots are observed across the Universe at brown dwarfs, X-ray pulsars, magnetars and planets. Within our own solar system, Jupiter possesses the only spatially resolvable example of these widespread phenomena. Jupiter's Northern X-ray aurora is concentrated into one of these polar hot spots, which is characterised by spectral lines of precipitating ~MeV/amu ions and pulsates on timescales of several 10s of minutes. This hot spot is located in the most poleward regions of Jupiter's multi-waveband aurora, where magnetic field lines map to the noon-dusk magnetopause . Given this mapping, the hot spots may be expected to be diagnostic of Jupiter's relationship with the solar wind and they do indeed change morphology, intensity and precipitating particle populations with changing solar wind conditions. We present XMM-Newton and Chandra X-ray observations from Summer 2016 (during Juno approach) and Spring 2007 (during New Horizons approach), when the observing geometry provided good visibility of Jupiter's South Pole. These observations reveal that Jupiter's Southern X-ray aurora also appears to be concentrated into a persistent hot spot. However, X-ray timing analysis suggests that, for these observations, Jupiter's Northern and Southern polar X-ray aurora behave independently.
Event Time
2pm
Venue
C36 Physics
Speaker
Will Dunn (UCL MSSL/ ESA/ Harvard Smithsonian CfA)
Recently interest in electronic, magnetic and optical materials based on inorganic, organic and hybrid nano-materials has increased significantly. Such new materials and novel device architectures have a potential to bring the technology and the research into the more than Moore and beyond Moore era [1]. The main quest is to find the best materials and devices for specific application. The most time efficient and cost effective approach to achieve that is to perform modelling and simulations of the numerous possibilities of materials and device architectures. For example, the modelling and simulation of electronic devices has been a vital tool in driving the development and comprehensive understanding of the semiconductor physics and devices operation. Analysis using state-of-the-art device modelling helped the process of miniaturization of transistors through the past half a century. Importantly, modelling and simulation enhanced knowledge in the field and contributed to a deeper understanding of the critical issues surrounding the device scaling and operation. To show the importance of the device modelling and simulations, in this seminar, I will present an exciting research carried out in the field of molecular electronics [2, 3] and quantum transport in next generation transistors for the semiconductor industry [4]. The main aim is to establish a link between the material properties, device architecture and device performance using hierarchical, multi-scaled simulation methodology and approach.
Event Time
3pm-4pm
Venue
C36 Physics
Speaker
Dr. Vihar Georgiev Electronic and Nanoscale Engineering Division, University of Glasgow
Event Time
3pm-4pm
Venue
C36 Physics
Speaker
Dr. Samuel Jarvis, Physics Department and Materials Science Institute, Lancaster University
You are invited to attend the launch event of our exciting new project, the Cumbria Innovations Platform. At this launch event you will find out more about how you can access support through workshops, management expertise and research and development opportunities.
Event Time
09:30-13:00
Venue
The Rheged Centre, Redhills, CA11 0DQ
The suppression of oscillation is an important topic of research in the context of coupled oscillators and has been studied in diverse fields such as physics, biology, and engineering. There are two distinct types of oscillation quenching processes: amplitude death (AD) and oscillation death (OD). In AD, coupled oscillators arrive to a common stable steady state which was unstable otherwise and thus form a stable homogeneous steady state. But, in the case of OD, oscillators populate different coupling dependent steady states and thus give rise to stable inhomogeneous steady states. AD is important in case of control application where suppression of unwanted oscillations is necessary. On the other hand, OD is a much more complex phenomenon because it induces inhomogeneity in a rather homogeneous system of oscillators that has strong connections and importance in the field of biology, physics, chemistry, etc. In our studies we have identified many aspects of different oscillation quenching states like: The first experimental evidence of the AD-OD transition, New oscillation quenching states, Revival of oscillations from death states. We report several possible routes to AD and OD in coupled periodic as well as chaotic oscillators under distinct coupling schemes. Using a rigorous bifurcation analysis we observe the transitions among limit cycle, AD, OD and other new oscillation quenching states and that enable us to switch between different physically accessible states. Our studies cover both theoretical and experimental aspect of oscillation quenching phenomena and their transitions.
Event Time
3pm-4pm
Venue
C36 Physics
Speaker
Dr. Debarati Ghosh, Department of Physics, University of Burdwan, West Bengal, India
Embedding a Josephson junction within a superconducting microwave cavity provides a novel way of exploring strongly non-linear quantum dynamics. Energy from a flow of Cooper pairs through the Josephson junction (driven by an applied voltage) pumps the cavity generating a large population of photons which in turn strongly affect the charge dynamics. This results in interesting non-equilibrium steady-states in the cavity which can have a range of non-classical properties. In this talk I will outline a simple theoretical model inspired by recent experimental work on Josephson junction-cavity systems and describe the coupled dynamics of the cavity photons and Cooper pairs.
Event Time
3pm-4pm
Venue
C36 Physics
Speaker
Prof. Andrew Armour University of Nottingham
Much of the extensive research of topological states of matter in the last few years has focused on topological classification of gaped systems. The question addressed in such classification is ``For a given dimension D and symmetry S, what topologically distinct classes of Hamiltonians exist?''. This question was mostly studied for systems of non-interacting electrons and for systems which are adiabatically connected to non-interacting electrons. Here, we study this question in a setup in which interactions between electrons create two dimensional fractionalized states that are not adiabatically connected to systems of non-interacting electrons. We classify the gaped states that may be created in effectively one dimensional chains embedded in such systems.
Event Time
3pm-4pm
Venue
C36 Physics
Speaker
Dr. Dganit Meidan, Department of Physics, Ben-Gurion university, Israel
The study of Lyman Alpha Emitters (LAEs) offers a valuable insight into the early stages of galaxy formation, and with first-year science results from the Multi Unit Spectroscopic Explorer (MUSE) we have now entered a new era in the detection of these distant faint galaxies. I will introduce MUSE and describe how its installation on the VLT has enabled the simultaneous detection and characterisation of hundreds of objects, including some galaxies that were previously completely undetected in deep Hubble imaging. I will discuss the steps necessary to construct a reliable luminosity function, describing our process for the robust, automated detection of LAEs in the MUSE deep-field blind spectroscopic data, and our estimates of these objects' Ly-alpha fluxes. I will describe our approach to determining the detection-completeness of the LAE sample, and show the MUSE LAE-Selection Function. Using this homogeneously selected sample, I will present the Ly-alpha luminosity function between z ~ 3.0 and z ~ 6.5 in the Hubble Deep Field South, together with preliminary results from the Hubble Ultra Deep Field, and discuss comparisons with the literature.
Event Time
1200 - 1300hrs
Venue
C36 Physics
Speaker
Alyssa Drake (RAS/CRAL-Observatoire de Lyon)
The South African National Space Agency (SANSA) was created in 2010 to coordinate all space related activities in South Africa. In 2011, two existing facilities were migrated into SANSA, including the Hermanus Magnetic Observatory (HMO) which then became responsible for the space science programme within SANSA. Activities of the space science programme include fundamental and applied space science research, the support of space facilitated science through data acquisition, the coordination and administration of scientific data, and the provision of space weather and magnetic technology products and services on a commercial and private basis. Through the Space Science Programme SANSA contributes to the worldwide network of magnetic observatories responsible for monitoring the Earth's magnetic field, and participates in global scientific projects. The programme also provides leadership in post-graduate student training as well as providing science advancement, public engagement, and learner and educator support. This presentation will give an overview of the activities of SANSA's programmes with emphasis on the research activities of the space science programme and South Africa's involvement in space weather. Possible collaboration activities will be highlighted.
Event Time
1400-1500
Venue
Bowland North Seminar Room 09
Speaker
Dr. Lee-Anne McKinnell, South African National Space Agency (SANSA)
We report on experiments performed within boundary (or Knudsen) layer of a rarefied gas. The noninvasive probe we use is a suspended nano-electro-mechanical string (NEMS), which interacts with 4 He gas at cryogenic temperatures. When the pressure P is decreased, a reduction of the damping force below molecular friction had been reported in Phys. Rev. Lett. 113, 136101, (2014) and never reproduced since. We demonstrate that this effect is independent of geometry, but dependent on temperature. Within the framework of kinetic theory, this reduction is interpreted as a rarefaction phenomenon, carried through the boundary layer by a deviation to the usual Maxwell-Boltzmann equilibrium distribution induced by surface scattering. Adsorbed atoms are shown to play a key role in the process.
Event Time
3pm-4pm
Venue
Fylde LT3
Speaker
Dr. Rasul Gazizulin, Institut Néel CNRS et Université Joseph Fourier, Grenoble
Throughout much of the eighties and nineties, systems engineer K. Eric Drexler was widely criticized (some might say castigated) for proposing a molecular manufacturing technology whereby macroscopic products could be built on an atom-by-atom basis under computer control [1, 2]. Drexler envisaged a technology which was, in essence, 3D printing with atoms via molecular assemblers and nanofactories. Although Drexler's proposals remain within the realms of science fiction (and, it's safe to say, will not be realised on the “one to two decade” time-scale that was over-enthusiastically claimed back in 2001 [3]), like all of the best sci fi, the molecular manufacturing concept prompts a consideration of the limits of fundamental physics (and physicochemical) principles. I will reappraise Drexler's computer-driven mechanochemistry concept in the context of the state of the art in scanning probe microscopy, where molecules and surfaces can now be imaged and modified at the single chemical bond limit (see Fig. [from Ref. [4]] for an example of the type of ultrahigh resolution now possible with dynamic force microscopy via a protocol introduced by Gross and co-workers [5]). Mechanochemistry on a bond-by-bond basis is now achieved by a growing number of groups worldwide [6]. What, therefore, are the prospects for automated assembly of nanoscopic or, indeed, microscopic objects an atom at a time, as Drexler imagined?
Event Time
3pm-4pm
Venue
Fylde LT3
Speaker
Prof. Philip Moriarty, Nottingham University
I will report on the first campaign with the new upgraded ATLAS-200 TW system in 2016. Electron acceleration has been studied in various injection schemes, yielding high-charge beams (up to nC level) with broadly tunable parameters (0.1-1.5 GeV). The combination of shock-front and colliding pulse injection yields two independently tunable, quasi-monochromatic electron bunches with prospect for driver-witness-type PWFA experiments. A few-cycle shadowgraphy/faraday rotation probe pulse was used for the study of wakefields and beam currents down to the low 1018 cm-3 density regime. In addition to the first observation of a fully broken bubble in the LWFA process, this diagnostic also proved the excitation of a wake by the primary LWFA electron bunch in a secondary plasma target as a first step towards true hybrid acceleration schemes.
Event Time
3.30 p.m.- 4.30 p.m.
Venue
C36 Physics
Speaker
Professor Stefan Karsch (LMU Munich and Max Planck Institute for Quantum Optics)
Space weather produces a wide range of effects on technology that includes damage to satellites and disruption of radio communication. The effects also extend to systems on the ground including power systems and pipelines. This talk will review the history of geomagnetic effects on ground-based technology, starting with the telegraph system, through to modern communication cables, power systems, pipelines and railways and show how knowledge about past effects is being used to protect the infrastructure that is critical for modern society.
Event Time
1400-1500
Venue
C36 Physics
Speaker
David Boteler, Natural Resources Canada
The Martian plasma system can be generalised as a series of plasma boundaries and regions arising from the interaction of the interplanetary solar environment with an intrinsic obstacle upstream of the planet. At Earth, this obstacle is called the magnetosphere, and results from the Earth's strong global dipole magnetic field. At Mars, the absence of a global dipole results in the planet's upper atmosphere and ionosphere interacting with the solar wind flow, forming an induced magnetosphere. Additionally, the extended Martian exosphere, and pockets of intense crustal magnetic fields add to the Martian obstacle, further complicating the interaction with the solar wind. In this talk I describe how I used in excess of 10 years of plasma observations by the Mars Express mission to study spatial and temporal variations in the Martian plasma system that are driven by variations in the interplanetary solar environment.
Event Time
1400-1500
Venue
County South D72
Speaker
Ben Hall, Lancaster University
Space Science Seminar: Towards Coupled Space Weather Models: extending the Met Office weather and climate model into the thermosphere (David Jackson)
Event Time
1400-1500
Venue
LUMS LT09
Speaker
David Jackson - Met Office
For several decades, superfluid helium has provided an almost unparalleled frontier of quantum physics research, especially in topics related to macroscopic quantum phenomena: traditionally both superfluid helium-4 and helium-3 have provided a natural but versatile window to many-body quantum physics. In this presentation I show how the versatility of superfluid helium-3 translates into a variety of emergent phenomena, touching seemingly distant fields such as cosmology and high-energy physics. In our experiments we have used a rotating ultra-low-temperature refrigerator, the superfluid sample being cooled down by a nuclear demagnetization stage and probed using nuclear magnetic resonance spectroscopy (NMR). One particularly useful NMR instrument can be constructed by trapping a Bose-Einstein condensate (BEC) of magnon quasiparticles within the superfluid. We have used such condensates in probing a variety of delicate phenomena such as other spin wave modes, including Higgs modes, and Majorana bound states. We have also studied propagation of self-trapped Q-ball solitons formed of magnons. Q-balls, if observed in the Universe, could shed light on mysteries such as the dark matter. As perhaps the most publicized topic of this presentation, I explain how we discovered the elusive half-quantum vortices in superfluid helium-3. The very name of quantum physics refers to the observation that fundamental concepts such as energy and momentum are quantised in the microscopic world. Therefore finding vortices carrying only half-a-quantum of circulation — seemingly breaking that rule — is not only intriguing, but manifests deep understanding of the underlying physics and quantum physics in general.
Event Time
3pm-4pm
Venue
C36 Physics
Speaker
Dr. Samuli Autti, Lancaster University.
Space Physics Seminar: Earth (Global Resonances of the Magnetosphere)
Event Time
1400-1500
Venue
C36 Physics
Speaker
Jasmine Sandhu, UCL MSSL
Observational Astrophysics Seminar - The origin of OB-type runaway stars
Event Time
1500 - 1600hrs
Venue
County South C89
Speaker
Jonathan Smoker (European Southern Observatory)
One of the most exciting topics at the frontier of high energy particle physics and cosmology is understanding the nature of dark matter. Observing its production and measuring its properties in high-energy particle collisions is a topic of high priority at the Large Hadron Collider. Many searches have already been undertaken and are ongoing, but have not yet observed dark matter. I will discuss the motivations for a new approach to searching for such invisible phenomena at the LHC. I will present the first results of such a measurement from the ATLAS experiment, placing them in context with existing approaches, discuss their implications, and give my perspective on the future of this measurement programme.
Event Time
13:45 - 14:45
Venue
Physics C36
Speaker
Darren Price, Manchester
Over the last 5 decades quantum effects have transformed the field of metrology (the science of measurement). This process will culminate next year with the re-definition of the SI-system when all SI base units will be defined in terms of fundamental constants of nature. The UK Quantum Initiative aims to develop disruptive applications based on novel quantum effects which could open up a whole new industry sector for the UK. The challenge for the metrological community is to develop test and validation methods for these new technologies and establish confidence in them. I this talk I'll discuss examples from both these aspects of quantum technology.
Event Time
1500-1600hrs
Venue
George Fox LT 5
Speaker
JT Janssen, Research Director of the National Physics Laboratory
Abstract: Stripped-envelope supernovae (SE-SNe) are a subset of core-collapse supernovae where the progenitor star has experienced severe mass loss during its evolution. The resulting pre-explosion star contains little or no hydrogen or helium at the moment of core-collapse, and this is visible in its photometric and spectroscopic evolution. They are an important component in the evolution of their local galactic environment and are the primary source of neutron star/black hole binaries in the Universe. However, despite being first identified as a distinct category in the 1980s it is only now that we are beginning to be build samples of sufficient size to investigate the populations properties. In this talk I will present the results of analysis on the largest sample of SE-SNe to dates, which indicates that these SNe have considerable diversity across mass, kinetic energy, specific kinetic energy, luminosity, temporal characteristics, and host environment. These results will then be linked back to some of the key questions in the field; what kind of progenitors give rise to these events and what kind of evolutionary pathways are available? How is mass lost and is there an indication as to the time-scales involved? How do SE-SNe link with other CC-SNe, superluminous-SNe, gamma-ray bursts, and strong sources of gravitational waves?
Event Time
1500 - 1600hrs
Venue
C36 Physics
Speaker
Simon Prentice (Liverpool John Moores University)
The next generation ATLAS Pixel Front-End chip and Readout
Event Time
13:45 - 14:45
Venue
Physics C36
Speaker
Timon Heim, Lawrence Berkeley National Laboratory
The CERN "Beamline for Schools" project.
Event Time
13:45 - 14:45
Venue
Physics C36
Speaker
Branislav Ristic, Lancaster University/CERN
The ATLAS Strip Detector Upgrade
Event Time
13:45 - 14:45
Venue
Physics C36
Speaker
Craig Sawyer, Rutherford Appleton Laboratory
Current status of Higgs -> WW measurements
Event Time
13:45 - 14:45
Venue
Physics C36
Speaker
Kathrin Becker, University of Oxford
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