什么是量子门隐形传态？

量子态隐形传态是一种量子信息协议，其中使用初始共享纠缠态，贝尔测量，经典通信和局部旋转在两方之间传输量子比特。显然，还有一种叫做量子门隐形传态的东西。

什么是量子门隐形传态？它的作用是什么？

我对模拟量子电路的可能应用特别感兴趣。

quantum-gate quantum-information teleportation

— 纪郎
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量子门隐形传态是在隐形状态下能够将量子门应用于未知状态的行为。这是可以使用图形状态描述基于度量的计算的方式之一。

通常，隐形传态通过具有未知的量子态而起作用 $|\psi\rangle$ 爱丽丝举行，并在贝尔状态两个量子比特 $|\Psi\rangle=(|00\rangle+|11\rangle)/\sqrt{2}$ 爱丽丝（Alice）和鲍勃（Bob）之间共享。爱丽丝进行贝尔状态测量，获取4个可能答案之一，而鲍勃则根据其4个状态之一的爱丽丝的测量结果保持其量子位 $|\psi\rangle,X|\psi\rangle,Z|\psi\rangle,ZX|\psi\rangle.$ 因此，一旦鲍勃了解爱丽丝得到了什么结果，他就可以通过应用适当的宝利斯来进行补偿。

令 $U$ 为1量子位unit。假设Alice和Bob份额 $(\mathbb{I}\otimes U)|\Psi\rangle$ 代替 $|\Psi\rangle$ 。如果他们重复传送协议，则Bob现在将具有 $U|\psi\rangle,UX|\psi\rangle,UZ|\psi\rangle,UZX|\psi\rangle$ 之一。，我们可以改写为 $U|\psi\rangle,(UXU^\dagger)U|\psi\rangle,(UZU^\dagger)U|\psi\rangle,(UZXU^\dagger)U|\psi\rangle.$ $U$ $(\mathbb{I},Z,X,XZ)$ $\sqrt{Z}=S$

即使您不仅需要Pauli门（的情况也是如此） $T=\sqrt{S}$ ), the compensations may be easier than implementing the gate directly. This is the basis of the construction of the fault-tolerant T gate.

In fact, you can do something similar to apply a controlled-NOT between a pair of qubits as well. This time, the state you need is $|\Psi\rangle_{A_1B_1}|\Psi\rangle_{A_1B_1}$ , and a controlled-NOT applied between $B_1$ and $B_2$ . This time, there are 16 possible compensating rotations, but all of them are just about how Pauli operations propagate through the action of a controlled-NOT and, again, that just gives Pauli operations out.

— DaftWullie
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I wish I could favourite answers, i created an account just to let you know how good this answer is

— John

If you click the "share" link below the answer, you'll get a shareable link directly to the answer, which you can add to your favorites. For the above one, it's quantumcomputing.stackexchange.com/a/1810/619

— user

"which we can rewrite as

| ψ ⟩

$|\psi\rangle$ ..." should be "

U | ψ ⟩

$U |\psi\rangle$ ".

— qbt937

@qbt937 well spotted! Thanks.

— DaftWullie

Gate teleportation is in principle a method that allows the creation of different gates from an available set of gates, by teleporting qubits through entangled states. An example of the use of this method, is the creation of the T gate from a Clifford set of gates in order to make the set universal. The construction in this particular case is done with the use of special T ancillae. The standard reference can be found in arXiv:quant-ph/9908010.

For simulating quantum circuits you can use the gate teleportation to move gates around the circuit with the use of ancillae qubit (number of ancillae depended on the number of gates).

— Panagiotis Barkoutsos
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