International Research Fellowship Program: Theoretical Investigations of Gravitational Systems at the Interface of the Classical and the Quantum

该奖项是根据2009年美国复苏和再投资法案（公法111-5）资助的。国际研究奖学金项目使美国科学家和工程师能够在国外进行9至24个月的研究。该计划的奖励为联合研究提供了机会，并利用独特或互补的设施、专业知识和国外的实验条件。该奖项将支持安德鲁·c·兰多诺博士与李·斯莫林博士在加拿大滑铁卢圆周理论物理研究所进行为期24个月的研究。近年来，我们对经典引力和量子引力的理解有了重大发展，它们在很大程度上是独立发展的。为了将这两个领域推进到下一个层次，在这个接口上进行调查是必要的。对量子引力的研究往往揭示了对经典引力本质的深刻见解，从而对经典引力的当前框架有了更丰富的理解，并提出了对既定理论的修改建议。此外，历史表明，量子引力的新革命往往来自对经典引力的新观点和新公式。PI正在进行各种研究项目，包括探索经典引力和量子引力的界面，最终目标是增强我们对这两种理论的理解，将它们推向下一个阶段。在正在探索的项目中，PI正在研究经典和量子引力中自旋的本质，以及从一个更大对称群的理论中出现的爱因斯坦引力。第一个项目需要研究几何的固有自旋的本质。从经典的角度来看，除了众所周知的自旋-轨道耦合是由重力磁类比产生的，有强有力的证据表明，自旋体本身通过其本征自旋产生了框架拖拽效应，这可能导致本征自旋与本征自旋的引力调制耦合。PI正在确定这种相互作用的规范无关性质，并研究中性粒子（如中子星中的天体物理中微子和中子）的潜在自旋诱导对结合可能产生的天体物理效应。所描述的第二个项目涉及探索从一个更基本的引力理论和更大的对称群中出现引力的后果。有强有力的证据表明，我们目前对基于洛伦兹群的引力的理解可能是基于德西特群的更基本理论的对称破缺相。这一证据来自观测，来自一个小的正宇宙常数的存在，以及从理论上讲，来自将自旋连接和四分体结合成一个德西特连接的可能性。PI正在研究瞬子解的性质及其在早期宇宙宇宙学中的可能意义。从量子的角度来看，PI正在研究一个基本的德西特对称是否能导致对Immirzi参数的本质的洞察，这个常数似乎是构建环量子引力所必需的，它在理论中起着基本的作用。黑洞熵的S描述。PI正在研究Immirzi参数的出现是否可能是德西特对称被洛伦兹对称打破的副产品，类似于QCD-theta参数的出现。

0853116RandonoThis award is funded under the American Recovery and Reinvestment Act of 2009 (Public Law 111-5).The International Research Fellowship Program enables U.S. scientists and engineers to conduct nine to twenty-four months of research abroad. The program's awards provide opportunities for joint research, and the use of unique or complementary facilities, expertise and experimental conditions abroad.This award will support a twenty-four-month research fellowship by Dr. Andrew C. Randono to work with Dr. Lee Smolin at Perimeter Institute for Theoretical Physics in Waterloo, Canada.In recent years, there have been significant developments in our understanding of classical and quantum gravity, which have evolved largely independently. Investigations at this interface are necessary in order to push both fields to the next level. The study of quantum gravity often reveals deep insights into the nature of classical gravity that lead to a richer understanding of the current framework of classical gravity as well as suggesting modifications to the established theory. In addition, history has shown that new revolutions in quantum gravity often emerge from new perspectives on and new formulations of classical gravity. The PI is conducting various research projects involving explorations of gravitational physics at the interface of classical and quantum gravity, with the ultimate goal enhancing our understanding of both theories to push them to the next stage. Among the projects being explored, the PI is investigating the nature of spin in classical and quantum gravity, and the emergence of Einstein gravity from a theory with a larger symmetry group. The first project entails a study of the nature of intrinsic spin to geometry. From the classical perspective, in addition to the well known spin-orbit coupling emerging from the gravitomagnetic analogy, there is strong evidence that spinors themselves give rise to a frame-dragging effect via their intrinsic spin, which could give rise to a gravitationally modulated coupling of intrinsic spin to intrinsic spin. The PI is determining the gauge independent properties of this interaction, and investigating the possible astrophysical effects from a potential spin induced pair binding of neutral particles such as astrophysical neutrinos and neutrons in a neutron star. The second project described involves an exploration of the consequences of the emergence of gravity from a more fundamental gravitational theory with a larger symmetry group. There is strong evidence that our current understanding of gravity based on the Lorentz group could be the symmetry broken phase of a more fundamental theory based on the de Sitter group. This evidence comes from the observationally from the existence of a small positive cosmological constant, and theoretically from the possibility of combining the spin connection and the tetrad into a single de Sitter connection. The PI is investigating the nature of instanton solutions and their possible significance in early universe cosmology. From the quantum perspective, the PI is investigating whether a fundamental de Sitter symmetry could lead to insight into the nature of the Immirzi parameter, a constant which appears to be necessary in the construction of Loop Quantum Gravity, which plays a fundamental role in the theory?s description of black hole entropy. The PI is investigating if the appearance of the Immirzi parameter could the by-product of the breaking of de Sitter symmetry to Lorentz symmetry, analogous to the emergence of the QCD-theta parameter.