
English: 
If we had a large quantum computer, what would we do with it?
In principle, a universal quantum computer can perform any logic operation
but the real advantage of using quantum computers comes only if we can find an algorithm
that uses the exponentially large amount of information that can be stored in the quantum states
to arrive at the solution in a smaller number of steps.
We have seen the example of the
quantum search algorithm which can find an item in an unsorted database
using a number of steps that is only the square root of the number of items.
Another famous application is the prime factoring of large numbers which has implications in cryptography.
But perhaps the most exciting application is to use quantum computers to simulate other quantum systems.
Precisely because of the exponentially large complexity of quantum states

Chinese: 
安德里亚·莫雷洛教授（Andrea Morello）
为您讲述量子计算机的概念
如果有了一台大型量子计算机
我们该用它做什么？
原则上来说 一台通用量子计算机
可以进行所有的逻辑运算
但要让量子计算机发挥最大优势
只有当我们找到了一种算法
可以充分利用储存在量子态里的海量信息
通过较少的步骤得到解法
我们已经学习了量子搜索算法的例子
从未分类的数据库中找到某一个条目
所需的步骤只是条目总数的平方根
另一个著名的应用是
大数字的素因子对密码学有重要影响
但也许最令人激动的应用就是
用量子计算机模拟其他量子系统
恰好因为量子态的高度复杂性

English: 
simulating quantum systems on a classical computer is exponentially hard.
This is why we cannot easily simulate
and design molecules of drugs or advanced materials on a normal computer.
Those are quantum systems whose complexity doubles every time we add even a single particle.
There are two main challenges ahead of us.
First, the hardware is very sophisticated and very delicate.
We will need many years of work from large, well funded research teams
before we can reliably build quantum computers with enough qubits to be really useful.
The good news is that we might be able to do so using a similar technology as what is already being used
to build the incredibly small silicone transistors we have in ordinary computers.
The other challenge is that of finding useful quantum algorithms.
At this moment, we only have a handful of
problems for which we know there is a quantum algorithm
that runs faster than a classical
one.
Part of the reason is that we don't have yet a quantum hardware powerful enough

Chinese: 
用传统计算机模拟量子系统非常困难
所以我们无法用传统计算机轻易地
模拟和设计药物分子或先进材料
就算我们每次只添加一个单粒子
量子系统的复杂性也会翻倍
目前我们面临着两大挑战
首先 它的硬件极为精密 而且非常脆弱
我们需要资源雄厚的大型研究团队
长达数十年的辛勤工作
才能造出拥有足够比特的量子计算机
好消息是 我们已经可以
用普通计算机制造微型硅晶体管
也许可以用相似的技术制作量子计算机
另一个挑战是 如何找到有用的量子算法
目前 只有在少数几个问题上
我们已知量子算法比传统方法更快

Chinese: 
原因之一 是我们的量子硬件不足以支持
量子软件工程师去测试和调试代码
所以我们希望量子的硬件
能够与量子软件携手发展
现在我们正处于量子革命的风口浪尖
它能为我们带来能力超越以往的计算机器
这是研究量子科学和工程的重要时刻
同样也是向21世纪最具变革性的技术
进行投资的重要时刻
本视频由澳大利亚新南威尔士大学电视台制作
许梦鸽翻译

English: 
for quantum software engineers to test and debug their code.
So we hope that the progress in quantum hardware will go hand in hand with that in quantum software.
We are now at the cusp of a quantum revolution that can provide us with computational machines
with a power never seen before.
It's a very exciting time to work in quantum science and engineering
and a very exciting time to invest in what could be the most transformational technology
of the 21st century.
