Holography, Entanglement, and Quantum Gravity

理论物理学中一些最重大的开放性问题直接存在于量子力学和引力的界面上。我们的宇宙是如何开始的？结局会怎样？什么是暗能量？黑洞里面是什么？ 这些问题中的每一个都是我们理解宇宙的基础，但是没有一个可以在不包括引力和量子物理的框架中得到回答。 弦理论就是这样一个框架，这个领域的最新发展使我们比以往任何时候都更接近于回答上面的一些基本问题。15年前，弦理论的研究人员发现了量子引力物理学和量子场论物理学之间惊人的联系，量子场论是物理学家用来描述基本粒子及其相互作用的众所周知的数学模型。通过这种被称为AdS/CFT对应的联系，以前不可能回答的量子引力问题可以转化为可以由量子场论回答的更简单的问题。 尽管有很多证据表明量子引力和量子场论之间的联系是正确的，但我们对为什么它是正确的却知之甚少。这种缺乏理解的情况使我们无法回答上述一些非常重要的问题。出于这个原因，我提出的研究的很大一部分是致力于调查为什么AdS/CFT对应工作。我最近的工作表明，这个问题的答案可能需要使用量子信息理论（量子计算机背后的理论）新兴领域的方法来研究量子场论。通过以这种新的方式思考场论，我相信我们会更好地理解为什么量子引力物理学有时可以从量子场论中产生。有了更深入的了解，我希望能够推广AdS/CFT对应，以获得一致的数学模型，帮助我们了解宇宙的开始，通过暗能量加速膨胀，以及它的结束。

Some of the grandest open questions in theoretical physics lie directly at the interface of quantum mechanics and gravity. How did our universe begin? How will it end? What is dark energy? What is inside a black hole? Each of these questions is fundamental to our understanding of the universe, but none of them can be answered in a framework that does not include both gravity and quantum physics. String theory is one such framework, and recent developments in this field have brought us closer than ever before to answering some of the fundamental questions above. Fifteen years ago, researchers in string theory discovered a stunning connection between the physics of quantum gravity and the physics of quantum field theories, the well-understood mathematical models that physicists use to describe elementary particles and their interactions. Through this connection, known as the AdS/CFT correspondence, quantum gravity questions that were previously impossible to answer can be translated into much simpler questions that can be answered by quantum field theory. Even though there is a lot of evidence that the connection between quantum gravity and quantum field theory is true, we have very little understanding of why it is true. This lack of understanding prevents us from answering some of the very important questions above. For this reason, a large part of my proposed research is dedicated to investigating why the AdS/CFT correspondence works. My recent work suggests that the answer to this question may require studying quantum field theory using methods from the emerging field of quantum information theory (the theory behind quantum computers). By thinking about field theories in this new way, I believe that we'll get a much better understanding why quantum gravitational physics can sometimes emerge from quantum field theories. With this deeper understanding, I hope to be able to generalize the AdS/CFT correspondence to obtain consistent mathematical models that can help us learn about our universe's beginning, its accelerating expansion through dark energy, and its end.