Abstract: The decay of the free neutron is the simplest example of nuclear beta decay and, as such, is the archetype for a wide variety of Weak Interaction processes. These include radioactivity, Big Bang Nucleosynthesis, and energy production in the sun. Additionally, The precise value of the free neutron lifetime, can, along with other data, be used to test the consistency of the Standard Model. Remarkably, the value of neutron lifetime can also help determine the atmospheric composition of Venus. Given the breadth of physics involved, it is disconcerting to note that, at present, measurements of the neutron lifetime by different methods are inconsistent. In this talk, I will discuss the physics of neutron decay and will review the strategies for the experimental determination of the neutron lifetime. I will discuss some of the experimental challenges and will attempt to provide some illumination of the current discrepant situation.
Abstract: The decay of the free neutron is the simplest example of nuclear beta decay and, as such, is the archetype for a wide variety of Weak Interaction processes. These include radioactivity, Big Bang Nucleosynthesis, and energy production in the sun. Additionally, The precise value of the free neutron lifetime, can, along with other data, be used to test the consistency of the Standard Model. Remarkably, the value of neutron lifetime can also help determine the atmospheric composition of Venus. Given the breadth of physics involved, it is disconcerting to note that, at present, measurements of the neutron lifetime by different methods are inconsistent. In this talk, I will discuss the physics of neutron decay and will review the strategies for the experimental determination of the neutron lifetime. I will discuss some of the experimental challenges and will attempt to provide some illumination of the current discrepant situation.
Abstract: Making everything run on electricity is a necessary step in the transition from fossil fuels.Starting that process immediatelyis also necessary, andhelpful both to the process and the environment.
Abstract: Making everything run on electricity is a necessary step in the transition from fossil fuels.Starting that process immediatelyis also necessary, andhelpful both to the process and the environment.
Title: Trapped-ion optical clocks: Telling time and testing physics at the quantum limit
Abstract: Optical transitions in trapped, laser-cooled ions can provide an extremely well-controlled frequency reference for atomic clocks. The most stable and accurate atomic clocks now make measurements with total uncertainty approaching 1×10-18. The Ion Storage Group at NIST develops optical clocks based on the 1S0-3P0 resonance in 27Al+. To perform precision spectroscopy on this atomic system we use the basic building block of a quantum computer, the two-qubit gate, which transfers information from 27Al+ to a second ion species held in the same trap. I will introduce these systems and present recent frequency comparisons between them and other optical clocks at NIST. These comparisons provide valuable data for international time/frequency standards and can test our fundamental theories including relativity and the Standard Model. I will also describe quantum metrology techniques that have allowed us to approach the quantum limit for stability in a 27Al+ single-ion clock.
Title: Trapped-ion optical clocks: Telling time and testing physics at the quantum limit
Abstract: Optical transitions in trapped, laser-cooled ions can provide an extremely well-controlled frequency reference for atomic clocks. The most stable and accurate atomic clocks now make measurements with total uncertainty approaching 1×10-18. The Ion Storage Group at NIST develops optical clocks based on the 1S0-3P0 resonance in 27Al+. To perform precision spectroscopy on this atomic system we use the basic building block of a quantum computer, the two-qubit gate, which transfers information from 27Al+ to a second ion species held in the same trap. I will introduce these systems and present recent frequency comparisons between them and other optical clocks at NIST. These comparisons provide valuable data for international time/frequency standards and can test our fundamental theories including relativity and the Standard Model. I will also describe quantum metrology techniques that have allowed us to approach the quantum limit for stability in a 27Al+ single-ion clock.
Title: Dynamics at the edge: charge fractionalization and near-stationary high energy state
Abstract: Ergodic many-body systems are expected to reach quasi-thermal equilibrium. Indeed, the energy distribution in quantum Hall edge modes with short-range interactions generally relaxes to a near-thermal asymptotic state that can be described in terms of charge fractionalization. Surprisingly, high-energy electrons injected into a single edge mode with finite range interactions can stabilize over a long time scale in a state far from a thermal one: the resulting many-body state consists of rapidly decaying transient components followed by a near-steady-state distribution with a peak near the injection energy.
Title: Dynamics at the edge: charge fractionalization and near-stationary high energy state
Abstract: Ergodic many-body systems are expected to reach quasi-thermal equilibrium. Indeed, the energy distribution in quantum Hall edge modes with short-range interactions generally relaxes to a near-thermal asymptotic state that can be described in terms of charge fractionalization. Surprisingly, high-energy electrons injected into a single edge mode with finite range interactions can stabilize over a long time scale in a state far from a thermal one: the resulting many-body state consists of rapidly decaying transient components followed by a near-steady-state distribution with a peak near the injection energy.
Title: Quantum Codes from Condensed Matter to Quantum Gravity
Abstract: I will explore the appearance of quantum codes in diverse contexts, from the toric code of condensed matter physics to holographic codes in quantum gravity. The contexts and implementations of these codes vary widely, but their structures have much in common and suggest a deeper connection between them.
Title: Quantum Codes from Condensed Matter to Quantum Gravity
Abstract: I will explore the appearance of quantum codes in diverse contexts, from the toric code of condensed matter physics to holographic codes in quantum gravity. The contexts and implementations of these codes vary widely, but their structures have much in common and suggest a deeper connection between them.
