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I've just finished a PhD in this area, topological quantum memories. Totally amazed at the level of this quantamagazine article. Superb stuff. They even manage
by mathgenius 9y ago
I've just finished a PhD in this area, topological quantum memories.
Totally amazed at the level of this quantamagazine article. Superb stuff. They even manage to explain string-nets. I keep thinking that you could make an interesting iPhone game out of this.
Actually it's nice to read a bit of a summary of the field, including the history.
Here is another good article discussing the open problem of the existence of a quantum memory [1]. The story goes like this: your hard-drive stores bits of information in little magnets. That is magnetic order, which falls into the symmetry-breaking paradigm discussed in the article. When you turn the computer off, it remembers what's on your harddrive. Those magnets keep the bits protected, by virtue of the "magnetic order". Now here's the question: can we do the same thing with quantum bits? Even theoretically, is it possible? Is there some kind of "quantum ordered system" that will protect a qubit?
[1] https://arxiv.org/abs/1411.6643 https://arxiv.org/abs/1411.6643
- igravious 9y ago> When you turn the computer off, it remembers what's on your harddrive. Weird analogy. The computer doesn't remember – the individual storage units on a hard drive don't care whether the machine around them has power or not They are indifferent to what's going on in the system which contains them as opposed to, say, the storage units in DRAM. Are you trying to say that at the moment all qubits we've made behave like the storage units in DRAM? In other words, while the system that contains them is powered on they remain in the same state but when the power is removed they become disordered? Aren't qubits an abstraction? I mean, qubit : bit :: qubit storage unit X : harddrive bit – or – qubit : bit :: qubit storage unit Y : DRAM bit – see what I mean?
- mathgenius 9y agoYeah this quantum memory is a passive memory, as opposed to active error correction, which is perhaps more akin to the DRAM side of things. The active error correction is what google etc. are working on right now. It's not clear if passive quantum memories will ever be built, or as i said, if they even can be theoretically built.
- selimthegrim 9y agoI know people have been looking into MBL and quantum memories, the problem seems to be that symmetries you'd need for topological phases either wreck MBL (beyond like SU(2)) or are the result of some quantum integrability (which also is not good for MBL) source: my advisor works on passive error correction
- mathgenius 9y agoVery interesting! I had to look at some of your other comments to find out that MBL is "many-body localization" which i've heard of but know very little about.
- igravious 9y agoCool, that's what I was trying to find out from you. Is this [Quantum Error Correction for Quantum Memories](https://arxiv.org/abs/1302.3428 https://arxiv.org/abs/1302.3428) from 2013, rev. 2015 by Barbara M. Terhal representative of the state of the art?
- mathgenius 9y agoYes this looks like a good reference.