Summary

1 | Date | 9/21/2018 | |||
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2 | Name | Stanislas Baturin | |||

3 | Affiliation | Enrico Fermi Institute, Physical Sciences Division, The University of Chicago | |||

4 | Home Page | ||||

5 | Colloquium Title | Pen and Paper Mathematical Models for State-of-the-Art Wakefield Accelerators | |||

6 | Abstract | The two beam wakefield acceleration is one of the most advanced ways to design compact GeV machines. First, a high current low energy beam decelerates in a structure (corrugated metal pipe, dielectric-loaded waveguide/resonator or plasma medium) leaving an electromagnetic wake (Cherenkov shock wave). Second, a low charge high energy beam follows the first beam and gets accelerated by the generated EM field. This accelerator scheme still lacks understanding of many aspects, such as beam stability, energy transfer efficiency. My talk will be focused on analytical methods and simple mathematical models to address these remaining challenges and gain detailed insight into important effects in dielectric and plasma wakefield acceleration. | |||

7 | Host | Philippe Piot | |||

8 | |||||

9 | Date | 9/28/2018 | |||

10 | Name | IVAN BOZOVIC | |||

11 | Affiliation | Brookhaven National Laboratory and Applied Physics Departments, Yale University | |||

12 | Home Page | ||||

13 | Colloquium Title | What makes cuprate superconductors so amazing? | |||

14 | Abstract | Superconductivity in cuprates has many mysterious facets, but the central question is why the critical temperature is so high. Our experiments target this question. I will present the results of a comprehensive study that took twelve years and thousands of cuprate samples, perhaps without precedence in Condensed Matter Physics. We have measured the key physical parameters of the superconducting and normal states and established their precise dependence on doping, temperature, and external fields. The findings bring in some great surprises, challenge the commonly held beliefs, rule out many models, and answer our initial question. References: Nature 537, 432 (2017); 536, 309 (2016); 472, 458 (2011); 455, 782 (2008); 422, 873 (2003); Science 326, 699 (2009); 316, 425 (2007); 297, 581 (2002); Nature Mater. 12, 877 (2013); 12, 387 (2013); 12, 1019 (2013); 12, 47 (2013); 11, 850 (2012); Nature Physics 10, 256 (2014); 7, 298 (2011); Nature Nanotech. 9, 443 (2014); 5, 516 (2010). | |||

15 | Host | Graduate Student Association | |||

16 | |||||

17 | Date | 10/12/2018 | |||

18 | Name | Andrei Patapenka | |||

19 | Affiliation | NIU, Physics Department / NICADD | |||

20 | Home Page | ||||

21 | Colloquium Title | The Fermilab Integrable Optics Test Accelerator and Its Nonlinear Dynamics | |||

22 | Abstract | The Fermilab Integrable Optics Test Accelerator facility enables the study of new methods for overcoming intensity-limiting phenomena in accelerators. The IOTA ring employs novel magnet technology for nonlinear beam accelerators and innovative techniques to compensate for detrimental beam dynamics effects. During the lecture, we will discuss the non-linear dynamics in the IOTA ring and present results of computer simulations of an electron beam by particle tracking, the Frequency Map Analysis, and the Normal Form. A brief introduction into particle accelerators and beams dynamics will be given in the beginning. We will also discuss the simulation methods and approaches for beam dynamics studies and analysis. | |||

23 | Host | Bela Erdelyi | |||

24 | |||||

25 | Date | 10/19/2018 | |||

26 | Name | Roland Winkler | |||

27 | Affiliation | Northern Illinois University | |||

28 | Home Page | ||||

29 | Colloquium Title | Asymmetric g Tensor in Low-Symmetry Two-Dimensional Hole Systems | |||

30 | Abstract | The Zeeman effect characterized by the g factor describes the coupling of the electron spin magnetic moment to a magnetic field. In low-symmetry systems, the g-factor becomes a tensor (i.e., a 3x3 matrix). For the longest time, it was widely believed that this g tensor only gives the energy splitting of the levels in a magnetic field. But there is more to it: recent experiments on GaAs/AlAs quantum wells showed that the g-tensor can also give rise to a peculiar spin precession of non-eigenstates with distinct dependencies of the spin dynamics on the direction of the magnetic field. A careful theoretical analysis of such experiments provides complete information about the tensor g. For a nontrivial g tensor it may happen, e.g., that spin non-eigenstates precess about an axis that is perpendicular to the applied magnetic field. | |||

31 | Host | Larry Lurio | |||

32 | |||||

33 | Date | 10/26/2018 | |||

34 | Name | valia allori | |||

35 | Affiliation | Northern Illinois University, Department of Philosophy | |||

36 | Home Page | https://valiaallori.com/ | |||

37 | Colloquium Title | Quantum Mechanics between History, Physics and Philosophy | |||

38 | Abstract | Quantum mechanics and scientific realism, the view that scientific theories are approximately true, are taken to be incompatible, given that quantum mechanics is riddled with paradoxes. At some point, mystery-free quantum theories were proposed to rescue scientific realism. However, if the wave function represents matter, and the wave function lives in configuration space, then it is mysterious how we seem to live in a three-dimensional world. In this talk I want to argue that a series of historical contingencies, rather than rational arguments, led people to focus on the wave function as material, and this is the root of all interpretational problems of quantum mechanics. | |||

39 | Host | Carol Thompson | |||

40 | |||||

41 | Date | 11/2/2018 | |||

42 | Name | Herman Schaumburg | |||

43 | Affiliation | Northern Illinois University | |||

44 | Home Page | ||||

45 | Colloquium Title | An Efficient N-body Simulation Algorithm | |||

46 | Abstract | The N-body problem is to track the motion of N bodies (or particles) each exerting pairwise forces upon one another. The number of these interactions scales with the square of N . Rather than computing the interactions between all the other particles and a single particle directly, the space containing the particles may be partitioned into boxes and the task of computing interactions for each particle is reduced to computing interactions between the particle and boxes external to it and interactions due to particles within the same box as the particle. By splitting the computation between the near and far particles, an approximate solution to the equations of motion may be computed efficiently while capturing the dynamics of particles in close encounters. The developed code within the beam physics group at NIU, Particles with High order Adaptive Dynamics (PHAD), is specialized for applications in electromagnetism. | |||

47 | Host | Bela Erdelyi | |||

48 | |||||

49 | Date | 11/9/2018 | |||

50 | Name | Wes Gohn | |||

51 | Affiliation | University of Kentucky | |||

52 | Home Page | http://www.pa.uky.edu/~gohn/ | |||

53 | Colloquium Title | Accelerating Physics with GPUs | |||

54 | Abstract | The graphics processing unit (GPU) has recently become a powerful tool for physics. It gives us the ability to increase computing speeds by massive parallelization of simple computing tasks. Various applications of using GPUs to improve computational speeds for physics will be discussed with an emphasis on particle physics and the Muon g-2 experiment in particular. The Muon g-2 experiment is using GPUs for fast online data processing in the data acquisition system, analysis of field moments, and Monte Carlo simulations on the Open Science Grid. Other experiments use GPUs for machine learning applications such as identification of jets or particle tracks. GPU implementations ranging from single desktop GPUs to the worlds' most powerful supercomputer are being used to accelerate the rate at which we can do physics. | |||

55 | Host | Michael Eads | |||

56 | |||||

57 | Date | 12/7/2018 | |||

58 | Name | Senior Seminar Poster Session | |||

59 | Affiliation | NIU Physics | |||

60 | Home Page | ||||

61 | Colloquium Title | Reserved for the Phys 498 and Phys 499H students presentations | |||

62 | Abstract | TBD | |||

63 | Host | Carol Thompson |

1 | Date | 4/5/2019 | |||
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2 | Name | Andre Schleife | |||

3 | Affiliation | University of Illinois at Urbana-Champaign | |||

4 | Home Page | ||||

5 | Colloquium Title | Excited electrons and real-time dynamics | |||

6 | Abstract | tba | |||

7 | Host | Roland Winkler | |||

8 | |||||

9 | Date | 4/26/2019 | |||

10 | Name | Senior Seminar and Projects Symposium | |||

11 | Affiliation | Physics Department Northern Illinois University | |||

12 | Home Page | ||||

13 | Colloquium Title | Reserved for the Phys 498 and Phys 499H students presentations | |||

14 | Abstract | TBD | |||

15 | Host | Carol Thompson |