A Pragmatic Approach to Adiabatic Quantum Computation

量子世界天生是平行的。量子对象可以同时存在于许多地方，并且通常具有属性的叠加，这些属性对于日常经典尺度上的对象来说是相互排斥的。1982年，理查德·费曼提出可以尝试使用这种并行性来加速计算。1982年，彼得·肖尔发现了一种算法，理论上可以在计算中使用这种并行性。自从这些早期的理论工作以来，量子计算理论一直在努力，同时试图找到一个可以实现这些想法的物理系统。从基于门的数字经典计算的成功中汲取队列，这些努力的大部分集中在基于门的数字量子计算上。然而，还有另一种选择，它更直接地利用了我们对物理过程的理解。大自然很擅长解决问题，比如找到最有效的方法将原子集合排列成晶体。自然界通过逐渐降低系统的温度来实现这一点，以便它最终能够稳定到最低能量状态-这一过程称为热退火。这被用于一系列经典的优化算法中。这种算法的量子版本，最初被称为量子退火-现在被称为绝热量子计算-最终可能被证明比基于门的模型更有效。事实上，一家加拿大公司，D-wave系统公司，已经尝试制造这样一台计算机，并取得了一些有希望的初步成果。然而，解释这种尝试是困难的，因为绝热量子计算的失败模式是经典的热退火。该项目旨在开发一种系统的方法来测试绝热量子计算是否使用实用的，基于物理的方法进行。在这样做的过程中，对如何优化这样一个系统的性能将产生新的见解。

The quantum world is innately parallel. Quantum objects may exist in many places at the same time and in general have a superposition of attributes that would be mutually exclusive for an object on the everyday classical scale. In 1982 Richard Feynman suggested that one might attempt to use this parallelism to speed up computation and in 1982 Peter Shor discovered an algorithm that could, theoretically, make use of it in a calculation.Since these early theoretical works, there has been a dramatic effort in the theory of quantum computation while at the same time trying to find a physical system where these ideas could be realized. Taking the queue from the success of digital, gate-based, classical computation, much of this effort has focused on gate based digital quantum computation. There is an alternative, however, which harnesses our understanding of physical process rather more directly. Nature is rather good at solving problems such as finding the most efficient way to arrange a collection of atoms into a crystal. Nature achieves this by gradually reducing the temperature of a system so that it can eventually settle to its lowest energy state - a process known as thermal annealing. This is used in a range of classical optimization algorithms.A quantum version of this, originally known as quantum annealing - now known as adiabatic quantum computation - may ultimately prove to be more effective for quantum computation than the gate based model. Indeed, a Canadian company, D-wave Systems, has attempted to make just such a computer with some promising initial results. Interpreting such attempts is difficult, however, since the failure mode of an adiabatic quantum computation is a classical thermal anneal. This project aims to develop a systematic way to test whether an adiabatic quantum computation has taken place using a pragmatic, physics based approach. In doing so, new insights into how to optimize the performance of such a system will result.