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?
> 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?
Yeah 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.
Cool, 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) from 2013, rev. 2015 by Barbara M. Terhal representative of the state of the art?
I 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
Very 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.
Fascinating work. Not only does it get at the very heart of connecting Nature with Mathematics. But there are some interesting novel electronics that can result.
More broadly is the emerging field of "Materials Informatics". Roughly ML algorithms applied to the search of stable new materials phases. As well as the processes required to create them.
Machine learning in materials informatics: recent applications and prospects
If I’m understanding the fundamentals of the science behind this article, basically researchers are messing around with the state of the orbitals [0] of the electron clouds of individual atoms and molecules in very cold condensates that are otherwise stable, provoking interesting states that defy the usual macroscopic interactions commonly observed in the 4 classic phases of matter?
The discrete/continuous analog would cellular automata and PDEs respectively.
Essentially, even if interaction is taking place, the hope is that such a regular and patterned formation could keep the qbits you care about, in perfect shape. There may be other interacting factors that oscillate but they are not used for storage, just for nonvolatility.
Betcha the theory turns out to be intractable because it'll be possible to encode the behaviors of algorithms into the properties of such ordered matter.
> "In the last three decades, condensed matter physicists have discovered a wonderland of exotic new phases of matter: emergent, collective states of interacting particles that are nothing like the solids, liquids and gases of common experience."
Stripped of most everything, the sentence reduces to "Physicists have discovered a wonderland".
I'm almost wishing I could embed a graphic. It's been a while since I've diagrammed the grammar of a sentence. I wonder if students are still being taught how to do that. As an exercise, more for myself than what I actually think you need, I'll just do the rest:
- What kind of physicists? Condensed matter physicists.
- When have the physicists discovered this wonderland? In the last three decades.
- A wonderland of what? Of exotic new phases of matter.
- What are these new phases like? They're emergent, collective states of interacting particles that are nothing like the solids, liquids and gases of common experience.
I hope that was the sentence you were referring to :)
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