Hybrid Rotaxanes as Scaleable Two Qubit-Gates for Quantum Information Processing

现代计算机以“位”为单位存储和处理信息。在一个比特内，信息要么存储为0，要么存储为1。我们现在拥有的巨大计算能力有一些局限性。例如，计算机将数字相乘的速度非常快——2 × 3 × 3 × 5 × 7 × 11 × 17 × 23 × 41 = 111094830。相反的操作在现代计算机上很慢，例如，如果给定111094830，计算机将很难计算出因子相乘。这种将大数分解成质数的操作看起来像是数学上的奇事，但却是现代世界信息加密的基础。另一种基于量子信息处理（QIP）的计算机将以一种非常不同的方式运行，使用量子力学的奇怪原理。这些信息将被存储在一个“量子位”中。与位相比，量子位存储的信息为0,1以及0到1之间所有数字的叠加。打个比方：如果一个比特像一个灯的开关——要么开，要么关——一个量子位就像一个调光开关，但它同时处于所有位置。在大多数情况下，量子计算机与普通计算机相比几乎没有优势，但在某些情况下——将大数分解为质数就是一个例子——量子计算机可以快速执行传统计算机无法实现的缓慢计算。已经报道了一些例子，其中进行了简单的计算，但还没有报道量子计算机可以进行复杂的计算。我们的建议是开发可以作为量子比特的分子，将它们连接在一起形成计算机的基本单元——一个双量子比特门——然后进一步发展化学，使我们能够用这些分子量子比特制备设备。

Modern computers work by storing and processing information in "bits". Within a bit the information is stored either as a 0 or 1. The huge computing power we now possess has some limitations. For example, computers are very fast at multiplying numbers together - 2 x 3 x 3 x 5 x 7 x 11 x 17 x 23 x 41 = 111094830. The reverse operation is slow on a modern computer, i.e. if you are given 111094830 a computer would find it difficult working out the factors multiplied together. This operation - factoring large numbers into primes - looks like a mathematical oddity, but is the basis of how information is encrypted in the modern world.An alternative computer - based on quantum information processing (QIP) - would operate in a very different way, using the strange principles of quantum mechanics. The information would be stored in a "qubit". In contrast to a bit, a qubit stores information as 0, 1 and the superposition of all numbers between 0 and 1. As an analogy: if a bit is like a light switch - either on or off - a qubit is like a dimmer switch, but one which is set at all positions simultaneously. In most cases a quantum computer would have few advantages over a normal computer, however in some cases - and factorising large numbers into primes is one example - then a quantum computer can perform a calculation quickly that is impossibly slow classically.Some examples have been reported where simple calculations have been performed, but no quantum computer has been reported that could carry out a complex computation. Our proposal is develop molecules that can act as qubits, link then together to form the fundamental units for a computer - a two-qubit gate - and then develop further chemistry that would allow us to prepare devices with these molecular qubits.