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First Von Neumann Architecture Quantum Computer
holy_calamity writes "The first computers with a von Neumann architecture, where a processor has access to RAM, appeared in the 1940s. Now the first quantum computing system with a von Neumann design has been made, at University of California Santa Barbara. Their quantum processor made up of two superconducting quantum bits can use a 2-bit "quantum RAM" to save entangled bit values into."
You, sir, are an idiot.
Will it run Quark?
A few months back I was thinking if we ever moved on from von Neumann or we kept using it. I can see were are we now, but I was thinking that after all those years there would be some improvements or a completely changed architecture.
To be considered a Von Neumann architecture, the program code needs to be stored in the same ram as the working data. That's the whole point of it. Otherwise, it's a Harvard architecture.
Given that the total ram capacity seems to be 2 bits (though, in all fairness, the bits are qu), it seems implausible that a useful program could fit in it.
Though I have not actually read TFA, I'd say to be skeptical about this. What they probably meant is "It has RAM." Unfortunately they used the completely wrong term for this.
Would half a nibble be enough for any serious operation? I know these are quantum bits so it is equivalent to the superposition of every possible value that those two bits could possibly represent which may be a lot but still it seems pretty useless at this point. I think it is too early to imagine what we could do with such a computer but the possibilities are there, maybe not just yet.
Karma: Positive (probably because of superiour intellect)
The term Von Neumann architecture has a variety of different meanings. One common meaning of the term is one in which instructions and data retrieval share a common bus. The original meaning was a bit more specific referring to a system that had a CPU, a separate memory for data and instructions, and input/output capability. Originally the real step forward was storing data and instructions together and treating them in some sense the same way which in many ways allowed a lot more flexibility in programming. Treating data and instructions the same way is something that still creates issues; SQL injection attacks are essentially just this: adding data that is formatted to look like instructions. But the upshot is that this use of the term- to use Von Neumann architecture to mean just having a working memory is a less common use of the term.
Moving on from there, the system in question uses superconductors to control qubits. This is one of a variety of different systems being proposed. For example, the most recent quantum computing article on Slashdot ahref=http://hardware.slashdot.org/story/11/08/31/1844252/Record-Low-Error-Rate-For-Qubit-Processorrel=url2html-5998http://hardware.slashdot.org/story/11/08/31/1844252/Record-Low-Error-Rate-For-Qubit-Processor> used ion traps. It is important to realize that different systems cannot be used together in any meaningful way. This means that improvements on any one type don't really carry over to the others. This is important if one is thinking in terms of when all this research will come together. A really good example of this is how early quantum computing used NMR systems http://en.wikipedia.org/wiki/Nuclear_magnetic_resonance_quantum_computer which was then abandoned due to scaling and other issues. A lot of what was learned with NMR systems could not be applied to later quantum computers.
If you can't copy a quantum state ...
Just can't wait for someone to figure out that introducing anti-mater into the device would give us one more bit: 0, 1 and -1.
Well at least I got a 'sir' out of it.
When the foot seeks the place of the head, the line is crossed. Know your place. Keep your place. Be a shoe.
A von Neumann architecture is characterized by having a single bus and address space for data and code -- not by whether data and/or code is stored in drum, delay-line, core/RAM, EEPROM (including flash), or something else entirely.
This implies several interesting things, such as the ability to write self-modifying code and the ability to exploit buffer overruns to execute arbitrary code.
Compare a typical Harvard-architecture microcontroller, where the code space is usually backed by flash or ROM, and the data space by SRAM, so the "processor has access to RAM" -- but it's not a von Neumann architecture, because they're separate address spaces on separate buses.
When I first saw the article, I thought they had created a quantum version of THIS:-
http://en.wikipedia.org/wiki/Von_Neumann_probe#Von_Neumann_probes
Oh well, we'll have to destroy the universe in using "classical" replicating machines instead.
Someone had to say it.
Everything I know about quantum computing leads me to believe this is a silly exercise.
- There's no benefit to having memory on the same chip as it's easier and more reliable to frame the problem and process the results with a non-quantum computer.
- Having anything that close to the qubits makes it that much harder to handle decoherence which remains an unsolved problem on large scales.
- "Conventional electrical circuits" aren't going to scale and if your quantum computing model can't scale, it's trash.
Publicity stunt?
Their quantum processor made up of two superconducting quantum bits can use a 2-bit "quantum RAM" to save entangled bit values into.
And you thought your 32-bit system needed upgrading.
Sheesh, evil *and* a jerk. -- Jade
-- http://en.wikipedia.org/wiki/Z3_(computer)#Relation_to_other_work
That's what this computer is good for.
You may laugh at the measly two bits, but don't you see that now all they have to do is build a Beowulf cluster of these and all your secrets are history, the singularity will be our benevolent dictator and nano-bots will eat the planet.
*golf clap*
I drank what? -- Socrates
That's one small step forwards, backwards, both or neither for electrons and one indeterminate state for quantumkind.
Anons need not reply. Questions end with a question mark.
Yes, but does it run Linux?
Where has all this quantum computing development brought the writing devices to now? Is there cheap (<$500) tech that can set the quantum spin value of electrons, photons, or of any other particle? Is there any spin-setting device that consumes less than the amount of energy differential between spin states it sets in order to set the state (in addition to the states' energy differential)?
--
make install -not war
Seriously if the US did not kidnap his ass he's ending up in Nuremberg for all those rocket they sent at London.
I haven't read the whole posting, but I highly disagree with the use of the term moderately with regards to significant in this context. First I would need to understand your usage of the term significant. Are you the type of person that considers a Hummer to be a monster truck or an economy vehicle for city driving? That would give be a better idea of how to interpret your use of the word significant. Then in relation, the use of the optional term moderately can be applied, but again... I'd have to know if you're the type of person that uses only half the 2kg tub of butter on a slice of bread because all things are good in moderation or if you believe moderation is a bit more practical of a term (relatively speaking).
:)
Please clarify or your entire statement must be dubbed invalid and utterly unreliable. Work and personal references as well as research references would be greatly appreciated.
P.S. - please don't forget to include bank account numbers and personal identification so we can properly audit your accounts for inconsistencies that could theoretically be used to prove you can't manage your own business and therefore should NOT be allowed to interfere with others.
It's not the one billion entangled bits so much. Its the terabyte of entangled kittens...
``Tension, apprehension & dissension have begun!'' - Duffy Wyg&, in Alfred Bester's _The Demolished Man_
The thing that really makes a processor "von Neumann" is the use of a common memory for data and instructions, PLUS the interpretation of a fetched word as data or an instruction depending on the current state of a sequential machine conditioned by the previous instruction - a system comparable with a Turing machine. It's not actually an optimal architecture for either robustness or speed, so I'm not sure why it's considered such a goal.
"No one will need more than 2 bits of memory for a personal quantum computer."
That's what this computer is good for.
FTFY.