@Strilanc: It's certainly anybody's freedom to refrain from replying anything for any reasons. I just like to stress the fact that in my earlier post I wrote that the paper referred to QPT at two places and went on to quote these two places that I meant. There was no intention at all to say "It...
Lacking knowledge, I couldn't understand much of what is written in Martinis's paper (reference given by Strilanc), not to say to attempt to counter-argue. However, I have the impression that the manner with which quantum tomography is mentioned at two places of the paper is a little bit biased...
@Truecrimson: Any scientific design is based on theory which may very well be sound. So one knows certainly what a piece of hardware is doing. But is it indeed doing that? The designer could have made a mistake (e.g. in a technical drawing), the manufacturer could have used wrong or poor...
@Truecrimson: Nothing in the real world is perfect, so certain probability of errors and the corresponding risks of damages etc. have always to be accepted, depending on the particular situation one (in contrast to other people) is in and one's own viewpoints ("philosophy"). In other words...
@Truecrimson: At the beginning of the paper, it says that the method is only applicable to pure states. Couldn't that be a quite severe limitation in the context of practical quantum computing in general?
@Strilanc : In my view verification subsumes error correction. Error correction deals with unavoidable noises while verification asks whether at a certain test moment a circuit or gate as such functions exactly as specified. Problems may occur due to design mistakes (e.g. some infrequently...
@Strilanc: Please kindly name a textbook, page no., and cite a few lines concerning the method of testing the states of qubits of the outputs of a quantum gate. Quantum error corrrection alone is not sufficient IMHO, unless you could cite something to the opposite. (In fact, consider a design...
@Strilanc: Actually I recently asked a physicist working in quantum computing research how one could know that, if a hardware quantum gate (not a more complex circuit!) is speicified to deliver output qubits of certain states, in case the input qubits are of certain other states, the hardware...
@Strilanc: Of course I, as layman, has to accept/follow experts' opinons. But is there any reason for me as layman to doubt the words of the author of the Wiki article, who apparently is an expert, that QPT is an infeasible task for sizable number of qubits? My deduction from that information...
@Strilanc: Even for classical hardware, there are constantly checks involved when your computer is running, only that you are not aware of them. One of them is the correct writing to disk storage when you save files. Because the classical computer hardware has been highly improved during the...
Wiki on quantum tomography claims that the work of QPT increases exponentially with the number of qubits involved and hence is an infeasible task for sizeable number of qubits. I think that this clearly implies the infeasibility of practical quantum computing, since one needs to verify the...
If I don'r err, Martinis' paper doesn't mention quantum tomography. Hence my layman's questions: (1) Could quantum tomography play at least some role (i.e. even if it plays a comparatively smaller one than quantum error correction) in affecting the issue of the possibility of practical...
I am not from physics but computer science. I am interested in the prospect of quantum computing in the future and would like eventually to learn a little bit about issues of hardware realizations of quantum computing from experts of this forum.