The best quantum processors make an error roughly once in every thousand operations. To become useful accelerators for scientific and enterprise problems, error rates must drop to one in a trillion or better.
令人惊讶的是：量子计算的错误率要求如此极端—从当前的最佳水平（千分之一）需要提升到万亿分之一，这相当于要求一个系统连续运行数万年而不出错。这种巨大的性能差距凸显了量子纠错技术的巨大挑战，也解释了为什么AI在量子计算中如此重要。
quantum blockchain
Do they really use a quantum blockchain? What exactly do they mean by that? Probably just a buzzword they're using to attract interest but aren't actually meaning literally.
A quantum blockchain, the pair suggests, would take advantage of entanglement, which in most cases, applies to situations regarding space. But it could also be useful for situations involving time, such as blockchains. In such a blockchain, the pair explains, transaction records could be represented by pairs of entangled photons linked in chronological order. When transfers take place, photons would be created and absorbed by the hubs that comprise a network. But since entangled photons are linked across time, they can be caused to have never existed at the same time.
=(α∣0⟩+β∣1⟩)(γ∣0⟩+δ∣1⟩)=αγ∣00⟩+αδ∣01⟩+βγ∣10⟩+βδ∣11⟩.
Might be the answer to an above inquiry.
we apply a Hadamard gate
What is the method to evaluate whether the output of a Hadamard gate should invert the bottom qubit or not?
is (0 + 1) / sqrt 2 high or low?
I'm missing something fundamental here.
equal
Frustrating wording here for me... Why is the word "equal" here at all. Doesn't seem to clarify anything.
the
For Computer Scientists, Microsoft put together a primer to Quantum Computing for us here: https://www.youtube.com/watch?v=F_Riqjdh2oM
I could understand some of it (through 40m), but think this series of articles will help immensely and I'll return to it after.
What does it mean for a matrix UUU to be unitary? It’s easiest to answer this question algebraically, where it simply means that U†U=IU^\dagger U = IU†U=I, that is, the adjoint of UUU, denoted U†U^\daggerU†, times UUU, is equal to the identity matrix. That adjoint is, recall, the complex transpose of UUU:
Starting to get a little bit more into linear algebra / complex numbers. I'd like to see this happen more gradually as I haven't used any of this since college.
this week’s announcement by Google that a machine made by a Canadian company, D-Wave Systems, which is marketed as “the world’s first commercial quantum computer”, had shown spectacular speed gains over conventional computers. “For a specific, carefully crafted proof-of-concept problem,” Google’s Hartmut Neven reported, “we achieved a 100-million-fold speed-up.”