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Is there any single-logical-qubit physical device out there as of end 2018?
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By my first impression, there are many-qubits computers out there and more to come, as to follow the press.
Now a closer look reveals that it's all about designing and building physical qubits.
Then, as it seems from further reading, you actually need quite many physical qubits (dozens or hundreds) to come close to a practically usable logical qubit.
So does it mean after all, nobody has yet built any single logical qubit?
Note. This question is meant to understand the state of the art as applyied to computing, not to blame it!
qubit quantum-technologies
asked 2 hours ago
J. Doe
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up vote
1
down vote
favorite
By my first impression, there are many-qubits computers out there and more to come, as to follow the press.
Now a closer look reveals that it's all about designing and building physical qubits.
Then, as it seems from further reading, you actually need quite many physical qubits (dozens or hundreds) to come close to a practically usable logical qubit.
So does it mean after all, nobody has yet built any single logical qubit?
Note. This question is meant to understand the state of the art as applyied to computing, not to blame it!
qubit quantum-technologies
asked 2 hours ago
J. Doe
1313
New contributor
J. Doe is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
add a comment |Â
up vote
1
down vote
favorite
up vote
1
down vote
favorite
By my first impression, there are many-qubits computers out there and more to come, as to follow the press.
Now a closer look reveals that it's all about designing and building physical qubits.
Then, as it seems from further reading, you actually need quite many physical qubits (dozens or hundreds) to come close to a practically usable logical qubit.
So does it mean after all, nobody has yet built any single logical qubit?
Note. This question is meant to understand the state of the art as applyied to computing, not to blame it!
qubit quantum-technologies
asked 2 hours ago
J. Doe
1313
New contributor
J. Doe is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
By my first impression, there are many-qubits computers out there and more to come, as to follow the press.
Now a closer look reveals that it's all about designing and building physical qubits.
Then, as it seems from further reading, you actually need quite many physical qubits (dozens or hundreds) to come close to a practically usable logical qubit.
So does it mean after all, nobody has yet built any single logical qubit?
Note. This question is meant to understand the state of the art as applyied to computing, not to blame it!
qubit quantum-technologies
qubit quantum-technologies
asked 2 hours ago
J. Doe
1313
New contributor
J. Doe is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
asked 2 hours ago
J. Doe
1313
New contributor
J. Doe is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
edited 1 hour ago
asked 2 hours ago
J. Doe
1313
New contributor
J. Doe is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
asked 2 hours ago
J. Doe
1313
asked 2 hours ago
J. Doe
1313
1313
New contributor
J. Doe is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
New contributor
J. Doe is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
J. Doe is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
add a comment |Â
add a comment |Â
1 Answer
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A logical qubit is a very fluid concept. You could use physical qubits as logical qubits. Or, you can encode multiple physical qubits as a single logical qubit. The more physical qubits you use, the better the resistance to noise. So, I would suggest that you question isn't exactly the right one to ask, and a better question is whether something useful can be done with existing quantum technology (in the direction of computation).
The long-term goal is to build quantum computers, which require logical operations to be performed with a suitable level of reliability (below the "fault-tolerant threshold"), that can be maintained for a long time. It's true that we're probably not quite there yet, even with a single logical qubit. I don't actually know how close current hardware is to achieving it. That doesn't mean that existing devices are entirely pointless.
There is a lot of research going on at the moment into "quantum supremacy", in other words, given the sort of noisy quantum devices of 50-100 qubits that are starting to appear, is there anything that we could do with them that is unequivocally better than anything we could do with a classical computer? The expectation is that we're somewhere around that threshold at the moment, but I'm not aware of anything that is definitive.
answered 1 hour ago
DaftWullie
10.1k1534
Good point about quantum supremacy! Thank you
– J. Doe
1 hour ago
1
"The expectation is that we're somewhere around that threshold at the moment" are you sure about this? I would say that the threshold is at ~50 perfect qubits, I am not sure the 50-100 ultra-noisy qubits we have now can be used to anything serious (it is my opinion, you can disagree of course).
– Nelimee
52 mins ago
add a comment |Â
1 Answer
1
active
oldest
votes
1 Answer
1
active
oldest
votes
active
oldest
votes
active
oldest
votes
up vote
3
down vote
A logical qubit is a very fluid concept. You could use physical qubits as logical qubits. Or, you can encode multiple physical qubits as a single logical qubit. The more physical qubits you use, the better the resistance to noise. So, I would suggest that you question isn't exactly the right one to ask, and a better question is whether something useful can be done with existing quantum technology (in the direction of computation).
The long-term goal is to build quantum computers, which require logical operations to be performed with a suitable level of reliability (below the "fault-tolerant threshold"), that can be maintained for a long time. It's true that we're probably not quite there yet, even with a single logical qubit. I don't actually know how close current hardware is to achieving it. That doesn't mean that existing devices are entirely pointless.
There is a lot of research going on at the moment into "quantum supremacy", in other words, given the sort of noisy quantum devices of 50-100 qubits that are starting to appear, is there anything that we could do with them that is unequivocally better than anything we could do with a classical computer? The expectation is that we're somewhere around that threshold at the moment, but I'm not aware of anything that is definitive.
answered 1 hour ago
DaftWullie
10.1k1534
Good point about quantum supremacy! Thank you
– J. Doe
1 hour ago
1
"The expectation is that we're somewhere around that threshold at the moment" are you sure about this? I would say that the threshold is at ~50 perfect qubits, I am not sure the 50-100 ultra-noisy qubits we have now can be used to anything serious (it is my opinion, you can disagree of course).
– Nelimee
52 mins ago
add a comment |Â
up vote
3
down vote
A logical qubit is a very fluid concept. You could use physical qubits as logical qubits. Or, you can encode multiple physical qubits as a single logical qubit. The more physical qubits you use, the better the resistance to noise. So, I would suggest that you question isn't exactly the right one to ask, and a better question is whether something useful can be done with existing quantum technology (in the direction of computation).
The long-term goal is to build quantum computers, which require logical operations to be performed with a suitable level of reliability (below the "fault-tolerant threshold"), that can be maintained for a long time. It's true that we're probably not quite there yet, even with a single logical qubit. I don't actually know how close current hardware is to achieving it. That doesn't mean that existing devices are entirely pointless.
There is a lot of research going on at the moment into "quantum supremacy", in other words, given the sort of noisy quantum devices of 50-100 qubits that are starting to appear, is there anything that we could do with them that is unequivocally better than anything we could do with a classical computer? The expectation is that we're somewhere around that threshold at the moment, but I'm not aware of anything that is definitive.
answered 1 hour ago
DaftWullie
10.1k1534
Good point about quantum supremacy! Thank you
– J. Doe
1 hour ago
1
"The expectation is that we're somewhere around that threshold at the moment" are you sure about this? I would say that the threshold is at ~50 perfect qubits, I am not sure the 50-100 ultra-noisy qubits we have now can be used to anything serious (it is my opinion, you can disagree of course).
– Nelimee
52 mins ago
add a comment |Â
up vote
3
down vote
up vote
3
down vote
A logical qubit is a very fluid concept. You could use physical qubits as logical qubits. Or, you can encode multiple physical qubits as a single logical qubit. The more physical qubits you use, the better the resistance to noise. So, I would suggest that you question isn't exactly the right one to ask, and a better question is whether something useful can be done with existing quantum technology (in the direction of computation).
The long-term goal is to build quantum computers, which require logical operations to be performed with a suitable level of reliability (below the "fault-tolerant threshold"), that can be maintained for a long time. It's true that we're probably not quite there yet, even with a single logical qubit. I don't actually know how close current hardware is to achieving it. That doesn't mean that existing devices are entirely pointless.
There is a lot of research going on at the moment into "quantum supremacy", in other words, given the sort of noisy quantum devices of 50-100 qubits that are starting to appear, is there anything that we could do with them that is unequivocally better than anything we could do with a classical computer? The expectation is that we're somewhere around that threshold at the moment, but I'm not aware of anything that is definitive.
answered 1 hour ago
DaftWullie
10.1k1534
A logical qubit is a very fluid concept. You could use physical qubits as logical qubits. Or, you can encode multiple physical qubits as a single logical qubit. The more physical qubits you use, the better the resistance to noise. So, I would suggest that you question isn't exactly the right one to ask, and a better question is whether something useful can be done with existing quantum technology (in the direction of computation).
The long-term goal is to build quantum computers, which require logical operations to be performed with a suitable level of reliability (below the "fault-tolerant threshold"), that can be maintained for a long time. It's true that we're probably not quite there yet, even with a single logical qubit. I don't actually know how close current hardware is to achieving it. That doesn't mean that existing devices are entirely pointless.
There is a lot of research going on at the moment into "quantum supremacy", in other words, given the sort of noisy quantum devices of 50-100 qubits that are starting to appear, is there anything that we could do with them that is unequivocally better than anything we could do with a classical computer? The expectation is that we're somewhere around that threshold at the moment, but I'm not aware of anything that is definitive.
answered 1 hour ago
DaftWullie
10.1k1534
answered 1 hour ago
DaftWullie
10.1k1534
answered 1 hour ago
DaftWullie
10.1k1534
answered 1 hour ago
DaftWullie
10.1k1534
10.1k1534
Good point about quantum supremacy! Thank you
– J. Doe
1 hour ago
1
"The expectation is that we're somewhere around that threshold at the moment" are you sure about this? I would say that the threshold is at ~50 perfect qubits, I am not sure the 50-100 ultra-noisy qubits we have now can be used to anything serious (it is my opinion, you can disagree of course).
– Nelimee
52 mins ago
add a comment |Â
Good point about quantum supremacy! Thank you
– J. Doe
1 hour ago
1
"The expectation is that we're somewhere around that threshold at the moment" are you sure about this? I would say that the threshold is at ~50 perfect qubits, I am not sure the 50-100 ultra-noisy qubits we have now can be used to anything serious (it is my opinion, you can disagree of course).
– Nelimee
52 mins ago
Good point about quantum supremacy! Thank you
– J. Doe
1 hour ago
Good point about quantum supremacy! Thank you
– J. Doe
1 hour ago
1
1
"The expectation is that we're somewhere around that threshold at the moment" are you sure about this? I would say that the threshold is at ~50 perfect qubits, I am not sure the 50-100 ultra-noisy qubits we have now can be used to anything serious (it is my opinion, you can disagree of course).
– Nelimee
52 mins ago
"The expectation is that we're somewhere around that threshold at the moment" are you sure about this? I would say that the threshold is at ~50 perfect qubits, I am not sure the 50-100 ultra-noisy qubits we have now can be used to anything serious (it is my opinion, you can disagree of course).
– Nelimee
52 mins ago
add a comment |Â
J. Doe is a new contributor. Be nice, and check out our Code of Conduct.
J. Doe is a new contributor. Be nice, and check out our Code of Conduct.
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