Department of Physics University of Texas at Austin 1 University Station C1600 Austin, Tx 78712-0264 512-471-1153 Voice 512-471-9637 Fax
MEL Oakes Undergraduate Lecture SeriesWednesday, 13 September 2006, 4:15pm, RLM 4.102 Dr. N. David Mermin, Cornell University "Relativity and Geometry" In 1905 Einstein constructed his special theory of relativity from two postulates: (1) No physical phenomena can distinguish among different uniformly moving frames of reference; (2) The speed of light in empty space is independent of the speed of the source of the light. The resulting description of space and time finds its most insightful description in the two-dimensional "space-time diagrams" invented by Minkowski in 1908. These are traditionally introduced after relativity has been developed along other lines, as a concise graphical summary of its analytical content. It is possible, however, to construct Minkowski's diagrams directly from Einstein's two postulates, using nothing more than some simple plane geometry. This geometric route into relativity is simpler and more powerful than other ways of developing the subject. Some of its elementary features may be unfamiliar even to professional relativists. PHYSICS COLLOQUIUM, Wednesday 27 September 2006, 4:15pm, RLM 4.102: Professor Wolfgang Schleich, University of Ulm "The Physics of Hurricanes" Abstract: Factorization of numbers using a quantum, security of codes due to the use of single photons and the similarity of the statistics of the energy levels of a billiard and the zeros of the Riemann zeta function point to an intimate connection between quantum mechanics and number theory. We illustrate this connection using two examples: i) The factorization of numbers using Gauss sums. In particular we report on a NMR experiment using this technique which has factored a six digits number. ii) The connection between the Riemann-Siegel formula describing the asymptotic behavior of the Riemann zeta function and Schroedinger cats. PHYSICS COLLOQUIUM, Wednesday 4 October 2006, 4:15pm, RLM 4.102: Professor Kerry Emanuel, Program in Atmospheres, Oceans, and Climate, Massachusetts Institute of Technology "The Physics of Hurricanes" Abstract: Hurricanes are nearly perfect examples of heat engines, driven by an evaporative enthalpy flux from the ocean to the atmosphere, and operating over a temperature differential of more than 100 K between the sea surface and the storm top. I will demonstrate that the thermodynamic cycle of a mature hurricane is very close to that of Carnot's maximally efficient cycle, and go on to talk about the physics of the genesis and intensification of hurricanes, focusing on remaining problems. PHYSICS COLLOQUIUM, Wednesday 18 October 2006, 4:15pm, RLM 4.102: Prof. Murray Holland, JILA/Dept of Physics, Uni. of Colorado "Quantum vortices in a rotating crystal of atoms and light" Abstract: A collection of ultracold atoms subject to a spatially periodic potential energy can exhibit many types of behavior analogous to electrons in a crystal lattice. This fact was profoundly demonstrated by recent experiments observing the superfluid to Mott-insulator transition for atoms in an optical lattice. An optical lattice consists of atoms, typically at nanokelvin temperatures, subject to a periodic potential produced by pairs of interfering laser beams. The analogy between ultracold atoms in optical lattices and electrons in crystal lattices is a manifestly rich one. If the optical lattice is rotating rapidly, many of the features associated with electrons in strong magnetic fields emerge. Even high correlated effects and quantum states like those underlying the fractional quantum Hall effect can potentially be realized. In this talk I will provide a few perspectives on the exciting possibilities that atomic physics is now offering, and present some results showing the effects of the quantization of circulation, the appearance of vortices, and some of the novel features of quantum phase transitions in these systems. PHYSICS COLLOQUIUM, Wednesday 8 November 2006, 4:15pm, RLM 4.102: Dr. John Kirtley, IBM "Experiments with superconducting pi-rings" Abstract: pi-rings are superconducting loops with at least one Josephson junction that have an intrinsic phase shift of pi in their order parameter upon circling the loop in the absence of externally applied fields or currents. They played a central role in the demonstration that the Cooper pairing symmetry in a number of hole- and electron-doped cuprate superconductors has predominantly dx2-y2 pairing symmetry, over a wide doping range. pi-rings have a 2-fold degenerate ground state in zero magnetic field, with spontaneously generated circulating supercurrents. This doubly degenerate ground state has been the basis of proposals for novel "quiet" qubits. The first pi-rings were made using techniques which would be difficult to extend to multiple devices, but recently a technique for reliably mass-producing photolithographically defined pi-rings has been developed using ramp-edge junctions in high-Tc cuprate-Nb rings. We will describe experiments using such rings as physical analogues to 1-d and 2-d spin systems, for mapping out the in-plane gap in optimally doped YBCO, for simplified Rapid Superconducting Flux Quantum (RSFQ) logic circuits with larger circuit parameter tolerances, and for fabricating a basic building block of proposed qubits with reduced interactions with the environment. Superconducting rings using ferromagnetic layers in the junction region to produce a pi-phase shift may ultimately be developed to the point where they can also be used for such applications. The question of whether the extra dissipation associated with the nodal regions in the cuprate gap function will be too large for applications using cuprate superconductors in qubits remains, but recent experimental work demonstrating quantum coherent effects in biepitaxial cuprate junctions is encouraging. PHYSICS COLLOQUIUM, Wednesday 29 November 2006, 4:15pm, RLM 4.102: Prof. Abhay Ashketar, Penn State University "Quantum Nature of the Big Bang" Abstract: According to general relativity, space-time ends at singularities and classical physics just stops. In particular, the big bang is regarded as The Beginning. However, general relativity is incomplete because it ignores quantum effects. Through simple models, I will illustrate how the quantum nature of space-time geometry sheds entirely new light on the nature of the big bang. Quantum physics does not stop there. Quantum geometry in the deep Planck regime can serve as a bridge to another, vast classical space-time. PHYSICS COLLOQUIUM, Wednesday 6 December 2006, 4:15pm, RLM 4.102: Dr. Doreen Wackeroth, UT-Austin, SUNY Buffalo "Theoretical Challenges in Searches for the Higgs Boson" Abstract: In the Standard Model of particle physics, particles gain mass via their interaction with the Higgs boson, which has yet to be proven to exist in experiments. The CERN Large Hadron Collider (LHC) is expected to either discover the Higgs boson, find SUSY particles, or discover other signals of new physics. In order to correctly interpret the data, theoretical calculations must match (or exceed) the experimental precision, which often requires the inclusion of radiative corrections. I first present the status and prospects of the search for the Higgs boson at the Fermilab Tevatron and CERN LHC colliders. I illustrate the impact of radiative corrections on one of the most promising discovery channels for the Higgs (Higgs produced in association with heavy quark pairs), within the frameworks of both the Standard Model, as well as its supersymmetric extension. I also discuss the important role of radiative corrections for indirect searches for the Higgs and/or potentially new physics.
In 1905 Einstein constructed his special theory of relativity from two postulates: (1) No physical phenomena can distinguish among different uniformly moving frames of reference; (2) The speed of light in empty space is independent of the speed of the source of the light. The resulting description of space and time finds its most insightful description in the two-dimensional "space-time diagrams" invented by Minkowski in 1908. These are traditionally introduced after relativity has been developed along other lines, as a concise graphical summary of its analytical content. It is possible, however, to construct Minkowski's diagrams directly from Einstein's two postulates, using nothing more than some simple plane geometry. This geometric route into relativity is simpler and more powerful than other ways of developing the subject. Some of its elementary features may be unfamiliar even to professional relativists.
PHYSICS COLLOQUIUM, Wednesday 27 September 2006, 4:15pm, RLM 4.102: Professor Wolfgang Schleich, University of Ulm "The Physics of Hurricanes" Abstract: Factorization of numbers using a quantum, security of codes due to the use of single photons and the similarity of the statistics of the energy levels of a billiard and the zeros of the Riemann zeta function point to an intimate connection between quantum mechanics and number theory. We illustrate this connection using two examples: i) The factorization of numbers using Gauss sums. In particular we report on a NMR experiment using this technique which has factored a six digits number. ii) The connection between the Riemann-Siegel formula describing the asymptotic behavior of the Riemann zeta function and Schroedinger cats. PHYSICS COLLOQUIUM, Wednesday 4 October 2006, 4:15pm, RLM 4.102: Professor Kerry Emanuel, Program in Atmospheres, Oceans, and Climate, Massachusetts Institute of Technology "The Physics of Hurricanes" Abstract: Hurricanes are nearly perfect examples of heat engines, driven by an evaporative enthalpy flux from the ocean to the atmosphere, and operating over a temperature differential of more than 100 K between the sea surface and the storm top. I will demonstrate that the thermodynamic cycle of a mature hurricane is very close to that of Carnot's maximally efficient cycle, and go on to talk about the physics of the genesis and intensification of hurricanes, focusing on remaining problems. PHYSICS COLLOQUIUM, Wednesday 18 October 2006, 4:15pm, RLM 4.102: Prof. Murray Holland, JILA/Dept of Physics, Uni. of Colorado "Quantum vortices in a rotating crystal of atoms and light" Abstract: A collection of ultracold atoms subject to a spatially periodic potential energy can exhibit many types of behavior analogous to electrons in a crystal lattice. This fact was profoundly demonstrated by recent experiments observing the superfluid to Mott-insulator transition for atoms in an optical lattice. An optical lattice consists of atoms, typically at nanokelvin temperatures, subject to a periodic potential produced by pairs of interfering laser beams. The analogy between ultracold atoms in optical lattices and electrons in crystal lattices is a manifestly rich one. If the optical lattice is rotating rapidly, many of the features associated with electrons in strong magnetic fields emerge. Even high correlated effects and quantum states like those underlying the fractional quantum Hall effect can potentially be realized. In this talk I will provide a few perspectives on the exciting possibilities that atomic physics is now offering, and present some results showing the effects of the quantization of circulation, the appearance of vortices, and some of the novel features of quantum phase transitions in these systems. PHYSICS COLLOQUIUM, Wednesday 8 November 2006, 4:15pm, RLM 4.102: Dr. John Kirtley, IBM "Experiments with superconducting pi-rings" Abstract: pi-rings are superconducting loops with at least one Josephson junction that have an intrinsic phase shift of pi in their order parameter upon circling the loop in the absence of externally applied fields or currents. They played a central role in the demonstration that the Cooper pairing symmetry in a number of hole- and electron-doped cuprate superconductors has predominantly dx2-y2 pairing symmetry, over a wide doping range. pi-rings have a 2-fold degenerate ground state in zero magnetic field, with spontaneously generated circulating supercurrents. This doubly degenerate ground state has been the basis of proposals for novel "quiet" qubits. The first pi-rings were made using techniques which would be difficult to extend to multiple devices, but recently a technique for reliably mass-producing photolithographically defined pi-rings has been developed using ramp-edge junctions in high-Tc cuprate-Nb rings. We will describe experiments using such rings as physical analogues to 1-d and 2-d spin systems, for mapping out the in-plane gap in optimally doped YBCO, for simplified Rapid Superconducting Flux Quantum (RSFQ) logic circuits with larger circuit parameter tolerances, and for fabricating a basic building block of proposed qubits with reduced interactions with the environment. Superconducting rings using ferromagnetic layers in the junction region to produce a pi-phase shift may ultimately be developed to the point where they can also be used for such applications. The question of whether the extra dissipation associated with the nodal regions in the cuprate gap function will be too large for applications using cuprate superconductors in qubits remains, but recent experimental work demonstrating quantum coherent effects in biepitaxial cuprate junctions is encouraging. PHYSICS COLLOQUIUM, Wednesday 29 November 2006, 4:15pm, RLM 4.102: Prof. Abhay Ashketar, Penn State University "Quantum Nature of the Big Bang" Abstract: According to general relativity, space-time ends at singularities and classical physics just stops. In particular, the big bang is regarded as The Beginning. However, general relativity is incomplete because it ignores quantum effects. Through simple models, I will illustrate how the quantum nature of space-time geometry sheds entirely new light on the nature of the big bang. Quantum physics does not stop there. Quantum geometry in the deep Planck regime can serve as a bridge to another, vast classical space-time. PHYSICS COLLOQUIUM, Wednesday 6 December 2006, 4:15pm, RLM 4.102: Dr. Doreen Wackeroth, UT-Austin, SUNY Buffalo "Theoretical Challenges in Searches for the Higgs Boson" Abstract: In the Standard Model of particle physics, particles gain mass via their interaction with the Higgs boson, which has yet to be proven to exist in experiments. The CERN Large Hadron Collider (LHC) is expected to either discover the Higgs boson, find SUSY particles, or discover other signals of new physics. In order to correctly interpret the data, theoretical calculations must match (or exceed) the experimental precision, which often requires the inclusion of radiative corrections. I first present the status and prospects of the search for the Higgs boson at the Fermilab Tevatron and CERN LHC colliders. I illustrate the impact of radiative corrections on one of the most promising discovery channels for the Higgs (Higgs produced in association with heavy quark pairs), within the frameworks of both the Standard Model, as well as its supersymmetric extension. I also discuss the important role of radiative corrections for indirect searches for the Higgs and/or potentially new physics.
Abstract: Factorization of numbers using a quantum, security of codes due to the use of single photons and the similarity of the statistics of the energy levels of a billiard and the zeros of the Riemann zeta function point to an intimate connection between quantum mechanics and number theory. We illustrate this connection using two examples: i) The factorization of numbers using Gauss sums. In particular we report on a NMR experiment using this technique which has factored a six digits number. ii) The connection between the Riemann-Siegel formula describing the asymptotic behavior of the Riemann zeta function and Schroedinger cats.
PHYSICS COLLOQUIUM, Wednesday 4 October 2006, 4:15pm, RLM 4.102: Professor Kerry Emanuel, Program in Atmospheres, Oceans, and Climate, Massachusetts Institute of Technology "The Physics of Hurricanes" Abstract: Hurricanes are nearly perfect examples of heat engines, driven by an evaporative enthalpy flux from the ocean to the atmosphere, and operating over a temperature differential of more than 100 K between the sea surface and the storm top. I will demonstrate that the thermodynamic cycle of a mature hurricane is very close to that of Carnot's maximally efficient cycle, and go on to talk about the physics of the genesis and intensification of hurricanes, focusing on remaining problems. PHYSICS COLLOQUIUM, Wednesday 18 October 2006, 4:15pm, RLM 4.102: Prof. Murray Holland, JILA/Dept of Physics, Uni. of Colorado "Quantum vortices in a rotating crystal of atoms and light" Abstract: A collection of ultracold atoms subject to a spatially periodic potential energy can exhibit many types of behavior analogous to electrons in a crystal lattice. This fact was profoundly demonstrated by recent experiments observing the superfluid to Mott-insulator transition for atoms in an optical lattice. An optical lattice consists of atoms, typically at nanokelvin temperatures, subject to a periodic potential produced by pairs of interfering laser beams. The analogy between ultracold atoms in optical lattices and electrons in crystal lattices is a manifestly rich one. If the optical lattice is rotating rapidly, many of the features associated with electrons in strong magnetic fields emerge. Even high correlated effects and quantum states like those underlying the fractional quantum Hall effect can potentially be realized. In this talk I will provide a few perspectives on the exciting possibilities that atomic physics is now offering, and present some results showing the effects of the quantization of circulation, the appearance of vortices, and some of the novel features of quantum phase transitions in these systems. PHYSICS COLLOQUIUM, Wednesday 8 November 2006, 4:15pm, RLM 4.102: Dr. John Kirtley, IBM "Experiments with superconducting pi-rings" Abstract: pi-rings are superconducting loops with at least one Josephson junction that have an intrinsic phase shift of pi in their order parameter upon circling the loop in the absence of externally applied fields or currents. They played a central role in the demonstration that the Cooper pairing symmetry in a number of hole- and electron-doped cuprate superconductors has predominantly dx2-y2 pairing symmetry, over a wide doping range. pi-rings have a 2-fold degenerate ground state in zero magnetic field, with spontaneously generated circulating supercurrents. This doubly degenerate ground state has been the basis of proposals for novel "quiet" qubits. The first pi-rings were made using techniques which would be difficult to extend to multiple devices, but recently a technique for reliably mass-producing photolithographically defined pi-rings has been developed using ramp-edge junctions in high-Tc cuprate-Nb rings. We will describe experiments using such rings as physical analogues to 1-d and 2-d spin systems, for mapping out the in-plane gap in optimally doped YBCO, for simplified Rapid Superconducting Flux Quantum (RSFQ) logic circuits with larger circuit parameter tolerances, and for fabricating a basic building block of proposed qubits with reduced interactions with the environment. Superconducting rings using ferromagnetic layers in the junction region to produce a pi-phase shift may ultimately be developed to the point where they can also be used for such applications. The question of whether the extra dissipation associated with the nodal regions in the cuprate gap function will be too large for applications using cuprate superconductors in qubits remains, but recent experimental work demonstrating quantum coherent effects in biepitaxial cuprate junctions is encouraging. PHYSICS COLLOQUIUM, Wednesday 29 November 2006, 4:15pm, RLM 4.102: Prof. Abhay Ashketar, Penn State University "Quantum Nature of the Big Bang" Abstract: According to general relativity, space-time ends at singularities and classical physics just stops. In particular, the big bang is regarded as The Beginning. However, general relativity is incomplete because it ignores quantum effects. Through simple models, I will illustrate how the quantum nature of space-time geometry sheds entirely new light on the nature of the big bang. Quantum physics does not stop there. Quantum geometry in the deep Planck regime can serve as a bridge to another, vast classical space-time. PHYSICS COLLOQUIUM, Wednesday 6 December 2006, 4:15pm, RLM 4.102: Dr. Doreen Wackeroth, UT-Austin, SUNY Buffalo "Theoretical Challenges in Searches for the Higgs Boson" Abstract: In the Standard Model of particle physics, particles gain mass via their interaction with the Higgs boson, which has yet to be proven to exist in experiments. The CERN Large Hadron Collider (LHC) is expected to either discover the Higgs boson, find SUSY particles, or discover other signals of new physics. In order to correctly interpret the data, theoretical calculations must match (or exceed) the experimental precision, which often requires the inclusion of radiative corrections. I first present the status and prospects of the search for the Higgs boson at the Fermilab Tevatron and CERN LHC colliders. I illustrate the impact of radiative corrections on one of the most promising discovery channels for the Higgs (Higgs produced in association with heavy quark pairs), within the frameworks of both the Standard Model, as well as its supersymmetric extension. I also discuss the important role of radiative corrections for indirect searches for the Higgs and/or potentially new physics.
Abstract: Hurricanes are nearly perfect examples of heat engines, driven by an evaporative enthalpy flux from the ocean to the atmosphere, and operating over a temperature differential of more than 100 K between the sea surface and the storm top. I will demonstrate that the thermodynamic cycle of a mature hurricane is very close to that of Carnot's maximally efficient cycle, and go on to talk about the physics of the genesis and intensification of hurricanes, focusing on remaining problems.
PHYSICS COLLOQUIUM, Wednesday 18 October 2006, 4:15pm, RLM 4.102: Prof. Murray Holland, JILA/Dept of Physics, Uni. of Colorado "Quantum vortices in a rotating crystal of atoms and light" Abstract: A collection of ultracold atoms subject to a spatially periodic potential energy can exhibit many types of behavior analogous to electrons in a crystal lattice. This fact was profoundly demonstrated by recent experiments observing the superfluid to Mott-insulator transition for atoms in an optical lattice. An optical lattice consists of atoms, typically at nanokelvin temperatures, subject to a periodic potential produced by pairs of interfering laser beams. The analogy between ultracold atoms in optical lattices and electrons in crystal lattices is a manifestly rich one. If the optical lattice is rotating rapidly, many of the features associated with electrons in strong magnetic fields emerge. Even high correlated effects and quantum states like those underlying the fractional quantum Hall effect can potentially be realized. In this talk I will provide a few perspectives on the exciting possibilities that atomic physics is now offering, and present some results showing the effects of the quantization of circulation, the appearance of vortices, and some of the novel features of quantum phase transitions in these systems. PHYSICS COLLOQUIUM, Wednesday 8 November 2006, 4:15pm, RLM 4.102: Dr. John Kirtley, IBM "Experiments with superconducting pi-rings" Abstract: pi-rings are superconducting loops with at least one Josephson junction that have an intrinsic phase shift of pi in their order parameter upon circling the loop in the absence of externally applied fields or currents. They played a central role in the demonstration that the Cooper pairing symmetry in a number of hole- and electron-doped cuprate superconductors has predominantly dx2-y2 pairing symmetry, over a wide doping range. pi-rings have a 2-fold degenerate ground state in zero magnetic field, with spontaneously generated circulating supercurrents. This doubly degenerate ground state has been the basis of proposals for novel "quiet" qubits. The first pi-rings were made using techniques which would be difficult to extend to multiple devices, but recently a technique for reliably mass-producing photolithographically defined pi-rings has been developed using ramp-edge junctions in high-Tc cuprate-Nb rings. We will describe experiments using such rings as physical analogues to 1-d and 2-d spin systems, for mapping out the in-plane gap in optimally doped YBCO, for simplified Rapid Superconducting Flux Quantum (RSFQ) logic circuits with larger circuit parameter tolerances, and for fabricating a basic building block of proposed qubits with reduced interactions with the environment. Superconducting rings using ferromagnetic layers in the junction region to produce a pi-phase shift may ultimately be developed to the point where they can also be used for such applications. The question of whether the extra dissipation associated with the nodal regions in the cuprate gap function will be too large for applications using cuprate superconductors in qubits remains, but recent experimental work demonstrating quantum coherent effects in biepitaxial cuprate junctions is encouraging. PHYSICS COLLOQUIUM, Wednesday 29 November 2006, 4:15pm, RLM 4.102: Prof. Abhay Ashketar, Penn State University "Quantum Nature of the Big Bang" Abstract: According to general relativity, space-time ends at singularities and classical physics just stops. In particular, the big bang is regarded as The Beginning. However, general relativity is incomplete because it ignores quantum effects. Through simple models, I will illustrate how the quantum nature of space-time geometry sheds entirely new light on the nature of the big bang. Quantum physics does not stop there. Quantum geometry in the deep Planck regime can serve as a bridge to another, vast classical space-time. PHYSICS COLLOQUIUM, Wednesday 6 December 2006, 4:15pm, RLM 4.102: Dr. Doreen Wackeroth, UT-Austin, SUNY Buffalo "Theoretical Challenges in Searches for the Higgs Boson" Abstract: In the Standard Model of particle physics, particles gain mass via their interaction with the Higgs boson, which has yet to be proven to exist in experiments. The CERN Large Hadron Collider (LHC) is expected to either discover the Higgs boson, find SUSY particles, or discover other signals of new physics. In order to correctly interpret the data, theoretical calculations must match (or exceed) the experimental precision, which often requires the inclusion of radiative corrections. I first present the status and prospects of the search for the Higgs boson at the Fermilab Tevatron and CERN LHC colliders. I illustrate the impact of radiative corrections on one of the most promising discovery channels for the Higgs (Higgs produced in association with heavy quark pairs), within the frameworks of both the Standard Model, as well as its supersymmetric extension. I also discuss the important role of radiative corrections for indirect searches for the Higgs and/or potentially new physics.
Abstract: A collection of ultracold atoms subject to a spatially periodic potential energy can exhibit many types of behavior analogous to electrons in a crystal lattice. This fact was profoundly demonstrated by recent experiments observing the superfluid to Mott-insulator transition for atoms in an optical lattice. An optical lattice consists of atoms, typically at nanokelvin temperatures, subject to a periodic potential produced by pairs of interfering laser beams. The analogy between ultracold atoms in optical lattices and electrons in crystal lattices is a manifestly rich one. If the optical lattice is rotating rapidly, many of the features associated with electrons in strong magnetic fields emerge. Even high correlated effects and quantum states like those underlying the fractional quantum Hall effect can potentially be realized. In this talk I will provide a few perspectives on the exciting possibilities that atomic physics is now offering, and present some results showing the effects of the quantization of circulation, the appearance of vortices, and some of the novel features of quantum phase transitions in these systems.
PHYSICS COLLOQUIUM, Wednesday 8 November 2006, 4:15pm, RLM 4.102: Dr. John Kirtley, IBM "Experiments with superconducting pi-rings" Abstract: pi-rings are superconducting loops with at least one Josephson junction that have an intrinsic phase shift of pi in their order parameter upon circling the loop in the absence of externally applied fields or currents. They played a central role in the demonstration that the Cooper pairing symmetry in a number of hole- and electron-doped cuprate superconductors has predominantly dx2-y2 pairing symmetry, over a wide doping range. pi-rings have a 2-fold degenerate ground state in zero magnetic field, with spontaneously generated circulating supercurrents. This doubly degenerate ground state has been the basis of proposals for novel "quiet" qubits. The first pi-rings were made using techniques which would be difficult to extend to multiple devices, but recently a technique for reliably mass-producing photolithographically defined pi-rings has been developed using ramp-edge junctions in high-Tc cuprate-Nb rings. We will describe experiments using such rings as physical analogues to 1-d and 2-d spin systems, for mapping out the in-plane gap in optimally doped YBCO, for simplified Rapid Superconducting Flux Quantum (RSFQ) logic circuits with larger circuit parameter tolerances, and for fabricating a basic building block of proposed qubits with reduced interactions with the environment. Superconducting rings using ferromagnetic layers in the junction region to produce a pi-phase shift may ultimately be developed to the point where they can also be used for such applications. The question of whether the extra dissipation associated with the nodal regions in the cuprate gap function will be too large for applications using cuprate superconductors in qubits remains, but recent experimental work demonstrating quantum coherent effects in biepitaxial cuprate junctions is encouraging. PHYSICS COLLOQUIUM, Wednesday 29 November 2006, 4:15pm, RLM 4.102: Prof. Abhay Ashketar, Penn State University "Quantum Nature of the Big Bang" Abstract: According to general relativity, space-time ends at singularities and classical physics just stops. In particular, the big bang is regarded as The Beginning. However, general relativity is incomplete because it ignores quantum effects. Through simple models, I will illustrate how the quantum nature of space-time geometry sheds entirely new light on the nature of the big bang. Quantum physics does not stop there. Quantum geometry in the deep Planck regime can serve as a bridge to another, vast classical space-time. PHYSICS COLLOQUIUM, Wednesday 6 December 2006, 4:15pm, RLM 4.102: Dr. Doreen Wackeroth, UT-Austin, SUNY Buffalo "Theoretical Challenges in Searches for the Higgs Boson" Abstract: In the Standard Model of particle physics, particles gain mass via their interaction with the Higgs boson, which has yet to be proven to exist in experiments. The CERN Large Hadron Collider (LHC) is expected to either discover the Higgs boson, find SUSY particles, or discover other signals of new physics. In order to correctly interpret the data, theoretical calculations must match (or exceed) the experimental precision, which often requires the inclusion of radiative corrections. I first present the status and prospects of the search for the Higgs boson at the Fermilab Tevatron and CERN LHC colliders. I illustrate the impact of radiative corrections on one of the most promising discovery channels for the Higgs (Higgs produced in association with heavy quark pairs), within the frameworks of both the Standard Model, as well as its supersymmetric extension. I also discuss the important role of radiative corrections for indirect searches for the Higgs and/or potentially new physics.
Abstract: pi-rings are superconducting loops with at least one Josephson junction that have an intrinsic phase shift of pi in their order parameter upon circling the loop in the absence of externally applied fields or currents. They played a central role in the demonstration that the Cooper pairing symmetry in a number of hole- and electron-doped cuprate superconductors has predominantly dx2-y2 pairing symmetry, over a wide doping range. pi-rings have a 2-fold degenerate ground state in zero magnetic field, with spontaneously generated circulating supercurrents. This doubly degenerate ground state has been the basis of proposals for novel "quiet" qubits. The first pi-rings were made using techniques which would be difficult to extend to multiple devices, but recently a technique for reliably mass-producing photolithographically defined pi-rings has been developed using ramp-edge junctions in high-Tc cuprate-Nb rings. We will describe experiments using such rings as physical analogues to 1-d and 2-d spin systems, for mapping out the in-plane gap in optimally doped YBCO, for simplified Rapid Superconducting Flux Quantum (RSFQ) logic circuits with larger circuit parameter tolerances, and for fabricating a basic building block of proposed qubits with reduced interactions with the environment. Superconducting rings using ferromagnetic layers in the junction region to produce a pi-phase shift may ultimately be developed to the point where they can also be used for such applications. The question of whether the extra dissipation associated with the nodal regions in the cuprate gap function will be too large for applications using cuprate superconductors in qubits remains, but recent experimental work demonstrating quantum coherent effects in biepitaxial cuprate junctions is encouraging.
PHYSICS COLLOQUIUM, Wednesday 29 November 2006, 4:15pm, RLM 4.102: Prof. Abhay Ashketar, Penn State University "Quantum Nature of the Big Bang" Abstract: According to general relativity, space-time ends at singularities and classical physics just stops. In particular, the big bang is regarded as The Beginning. However, general relativity is incomplete because it ignores quantum effects. Through simple models, I will illustrate how the quantum nature of space-time geometry sheds entirely new light on the nature of the big bang. Quantum physics does not stop there. Quantum geometry in the deep Planck regime can serve as a bridge to another, vast classical space-time. PHYSICS COLLOQUIUM, Wednesday 6 December 2006, 4:15pm, RLM 4.102: Dr. Doreen Wackeroth, UT-Austin, SUNY Buffalo "Theoretical Challenges in Searches for the Higgs Boson" Abstract: In the Standard Model of particle physics, particles gain mass via their interaction with the Higgs boson, which has yet to be proven to exist in experiments. The CERN Large Hadron Collider (LHC) is expected to either discover the Higgs boson, find SUSY particles, or discover other signals of new physics. In order to correctly interpret the data, theoretical calculations must match (or exceed) the experimental precision, which often requires the inclusion of radiative corrections. I first present the status and prospects of the search for the Higgs boson at the Fermilab Tevatron and CERN LHC colliders. I illustrate the impact of radiative corrections on one of the most promising discovery channels for the Higgs (Higgs produced in association with heavy quark pairs), within the frameworks of both the Standard Model, as well as its supersymmetric extension. I also discuss the important role of radiative corrections for indirect searches for the Higgs and/or potentially new physics.
Abstract: According to general relativity, space-time ends at singularities and classical physics just stops. In particular, the big bang is regarded as The Beginning. However, general relativity is incomplete because it ignores quantum effects. Through simple models, I will illustrate how the quantum nature of space-time geometry sheds entirely new light on the nature of the big bang. Quantum physics does not stop there. Quantum geometry in the deep Planck regime can serve as a bridge to another, vast classical space-time.
PHYSICS COLLOQUIUM, Wednesday 6 December 2006, 4:15pm, RLM 4.102: Dr. Doreen Wackeroth, UT-Austin, SUNY Buffalo "Theoretical Challenges in Searches for the Higgs Boson" Abstract: In the Standard Model of particle physics, particles gain mass via their interaction with the Higgs boson, which has yet to be proven to exist in experiments. The CERN Large Hadron Collider (LHC) is expected to either discover the Higgs boson, find SUSY particles, or discover other signals of new physics. In order to correctly interpret the data, theoretical calculations must match (or exceed) the experimental precision, which often requires the inclusion of radiative corrections. I first present the status and prospects of the search for the Higgs boson at the Fermilab Tevatron and CERN LHC colliders. I illustrate the impact of radiative corrections on one of the most promising discovery channels for the Higgs (Higgs produced in association with heavy quark pairs), within the frameworks of both the Standard Model, as well as its supersymmetric extension. I also discuss the important role of radiative corrections for indirect searches for the Higgs and/or potentially new physics.
Abstract: In the Standard Model of particle physics, particles gain mass via their interaction with the Higgs boson, which has yet to be proven to exist in experiments. The CERN Large Hadron Collider (LHC) is expected to either discover the Higgs boson, find SUSY particles, or discover other signals of new physics. In order to correctly interpret the data, theoretical calculations must match (or exceed) the experimental precision, which often requires the inclusion of radiative corrections. I first present the status and prospects of the search for the Higgs boson at the Fermilab Tevatron and CERN LHC colliders. I illustrate the impact of radiative corrections on one of the most promising discovery channels for the Higgs (Higgs produced in association with heavy quark pairs), within the frameworks of both the Standard Model, as well as its supersymmetric extension. I also discuss the important role of radiative corrections for indirect searches for the Higgs and/or potentially new physics.
I first present the status and prospects of the search for the Higgs boson at the Fermilab Tevatron and CERN LHC colliders. I illustrate the impact of radiative corrections on one of the most promising discovery channels for the Higgs (Higgs produced in association with heavy quark pairs), within the frameworks of both the Standard Model, as well as its supersymmetric extension. I also discuss the important role of radiative corrections for indirect searches for the Higgs and/or potentially new physics.
