IBM's quantum computing capabilities — entangled 18-qubit GHZ states and high coherence timesAny few-qubit versions of Lloyd's “weakly-coupled-array” quantum computing?
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IBM's quantum computing capabilities — entangled 18-qubit GHZ states and high coherence times
Any few-qubit versions of Lloyd's “weakly-coupled-array” quantum computing?
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$begingroup$
Here's a blog post that corresponds with what IBM presented at the 2019 March Meeting.
In this post, they claim they've measured qubit T1 relaxation times above 500 microseconds, and claim that they've seen evidence of genuinely entangled 18-qubit GHZ states.
This is far beyond anything that I've seen in published literature. The best results as far as I can find are 12 genuinely entangled qubits (up from 10) from the Pan group in China (1), and ~160 microsecond T1 times (2), also from IBM, but using a 3D cavity transmon qubit.
Question:
Assuming the claims are credible, what sort of advancements in fabrication (for the long coherence times) and microwave technology (for large entangled states) could allow such fast progress?
physical-realization experiment ibm
edited May 13 at 16:19
Sanchayan Dutta
7,28741659
asked May 13 at 12:09
psitaepsitae
483216
$endgroup$
add a comment |
$begingroup$
Here's a blog post that corresponds with what IBM presented at the 2019 March Meeting.
In this post, they claim they've measured qubit T1 relaxation times above 500 microseconds, and claim that they've seen evidence of genuinely entangled 18-qubit GHZ states.
This is far beyond anything that I've seen in published literature. The best results as far as I can find are 12 genuinely entangled qubits (up from 10) from the Pan group in China (1), and ~160 microsecond T1 times (2), also from IBM, but using a 3D cavity transmon qubit.
Question:
Assuming the claims are credible, what sort of advancements in fabrication (for the long coherence times) and microwave technology (for large entangled states) could allow such fast progress?
physical-realization experiment ibm
edited May 13 at 16:19
Sanchayan Dutta
7,28741659
asked May 13 at 12:09
psitaepsitae
483216
$endgroup$
add a comment |
$begingroup$
Here's a blog post that corresponds with what IBM presented at the 2019 March Meeting.
In this post, they claim they've measured qubit T1 relaxation times above 500 microseconds, and claim that they've seen evidence of genuinely entangled 18-qubit GHZ states.
This is far beyond anything that I've seen in published literature. The best results as far as I can find are 12 genuinely entangled qubits (up from 10) from the Pan group in China (1), and ~160 microsecond T1 times (2), also from IBM, but using a 3D cavity transmon qubit.
Question:
Assuming the claims are credible, what sort of advancements in fabrication (for the long coherence times) and microwave technology (for large entangled states) could allow such fast progress?
physical-realization experiment ibm
edited May 13 at 16:19
Sanchayan Dutta
7,28741659
asked May 13 at 12:09
psitaepsitae
483216
$endgroup$
Here's a blog post that corresponds with what IBM presented at the 2019 March Meeting.
In this post, they claim they've measured qubit T1 relaxation times above 500 microseconds, and claim that they've seen evidence of genuinely entangled 18-qubit GHZ states.
This is far beyond anything that I've seen in published literature. The best results as far as I can find are 12 genuinely entangled qubits (up from 10) from the Pan group in China (1), and ~160 microsecond T1 times (2), also from IBM, but using a 3D cavity transmon qubit.
Question:
Assuming the claims are credible, what sort of advancements in fabrication (for the long coherence times) and microwave technology (for large entangled states) could allow such fast progress?
physical-realization experiment ibm
physical-realization experiment ibm
edited May 13 at 16:19
Sanchayan Dutta
7,28741659
asked May 13 at 12:09
psitaepsitae
483216
edited May 13 at 16:19
Sanchayan Dutta
7,28741659
asked May 13 at 12:09
psitaepsitae
483216
edited May 13 at 16:19
Sanchayan Dutta
7,28741659
edited May 13 at 16:19
Sanchayan Dutta
7,28741659
edited May 13 at 16:19
Sanchayan Dutta
7,28741659
7,28741659
asked May 13 at 12:09
psitaepsitae
483216
asked May 13 at 12:09
psitaepsitae
483216
asked May 13 at 12:09
psitaepsitae
483216
483216
add a comment |
add a comment |
1 Answer
1
active
oldest
votes
$begingroup$
So, to begin, I would point out that the 500 micosec T1 time is for a single qubit in isolation, while the GHZ results are on a 20 qubit device. This device has an avg T1 time of around ~75 microsec.
The GHZ results were done by Ken Wei from IBM, and will be published shortly.
In short, the circuit is a standard GHZ building circuit, with a hadamard gate followed by a chain of CNOT gates (As pictured above). These gates are ordered in such a way as to minimize the construction time by running CNOT gates in parallel on the device(not pictured above). Then there is a layer of phase gates (U1 gates in the IBM notation), followed by the reverse sequence of gates to undo the GHZ state. The U1 layer in the middle gives the states a phase that is then kicked-back in the unrolling at the end, and measured by the top qubit.
To make everything happen, you need high-fidelity CNOT gates, and high-fidelity parallel CNOT gates. In addition, and equally important, you need to be able to correct for measurement errors in the final result. Think of this as measurement tomography if you like. This is a part of the IBM Qiskit Ignis package (qiskit.org). Further details of how all this works together will be in the forthcoming publication
Update:
Here is the paper: Wei, Ken X., et al. "Verifying Multipartite Entangled GHZ States via Multiple Quantum Coherences" arXiv preprint arXiv:1905.05720 (2019).
edited May 15 at 13:30
Sanchayan Dutta
7,28741659
answered May 13 at 14:14
Paul NationPaul Nation
18613
$endgroup$
2
$begingroup$
Hi Paul. You're clearly from the IBM group. It seems like careful calibration and the circuit above might be enough for the GHZ result. I'm quite impressed with the 500us coherence times too. Is there some technological breakthrough, maybe in the fab process, that caused just a jump in the coherence times?
$endgroup$
– psitae
May 13 at 16:15
add a comment |
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1 Answer
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1 Answer
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$begingroup$
So, to begin, I would point out that the 500 micosec T1 time is for a single qubit in isolation, while the GHZ results are on a 20 qubit device. This device has an avg T1 time of around ~75 microsec.
The GHZ results were done by Ken Wei from IBM, and will be published shortly.
In short, the circuit is a standard GHZ building circuit, with a hadamard gate followed by a chain of CNOT gates (As pictured above). These gates are ordered in such a way as to minimize the construction time by running CNOT gates in parallel on the device(not pictured above). Then there is a layer of phase gates (U1 gates in the IBM notation), followed by the reverse sequence of gates to undo the GHZ state. The U1 layer in the middle gives the states a phase that is then kicked-back in the unrolling at the end, and measured by the top qubit.
To make everything happen, you need high-fidelity CNOT gates, and high-fidelity parallel CNOT gates. In addition, and equally important, you need to be able to correct for measurement errors in the final result. Think of this as measurement tomography if you like. This is a part of the IBM Qiskit Ignis package (qiskit.org). Further details of how all this works together will be in the forthcoming publication
Update:
Here is the paper: Wei, Ken X., et al. "Verifying Multipartite Entangled GHZ States via Multiple Quantum Coherences" arXiv preprint arXiv:1905.05720 (2019).
edited May 15 at 13:30
Sanchayan Dutta
7,28741659
answered May 13 at 14:14
Paul NationPaul Nation
18613
$endgroup$
2
$begingroup$
Hi Paul. You're clearly from the IBM group. It seems like careful calibration and the circuit above might be enough for the GHZ result. I'm quite impressed with the 500us coherence times too. Is there some technological breakthrough, maybe in the fab process, that caused just a jump in the coherence times?
$endgroup$
– psitae
May 13 at 16:15
add a comment |
$begingroup$
So, to begin, I would point out that the 500 micosec T1 time is for a single qubit in isolation, while the GHZ results are on a 20 qubit device. This device has an avg T1 time of around ~75 microsec.
The GHZ results were done by Ken Wei from IBM, and will be published shortly.
In short, the circuit is a standard GHZ building circuit, with a hadamard gate followed by a chain of CNOT gates (As pictured above). These gates are ordered in such a way as to minimize the construction time by running CNOT gates in parallel on the device(not pictured above). Then there is a layer of phase gates (U1 gates in the IBM notation), followed by the reverse sequence of gates to undo the GHZ state. The U1 layer in the middle gives the states a phase that is then kicked-back in the unrolling at the end, and measured by the top qubit.
To make everything happen, you need high-fidelity CNOT gates, and high-fidelity parallel CNOT gates. In addition, and equally important, you need to be able to correct for measurement errors in the final result. Think of this as measurement tomography if you like. This is a part of the IBM Qiskit Ignis package (qiskit.org). Further details of how all this works together will be in the forthcoming publication
Update:
Here is the paper: Wei, Ken X., et al. "Verifying Multipartite Entangled GHZ States via Multiple Quantum Coherences" arXiv preprint arXiv:1905.05720 (2019).
edited May 15 at 13:30
Sanchayan Dutta
7,28741659
answered May 13 at 14:14
Paul NationPaul Nation
18613
$endgroup$
2
$begingroup$
Hi Paul. You're clearly from the IBM group. It seems like careful calibration and the circuit above might be enough for the GHZ result. I'm quite impressed with the 500us coherence times too. Is there some technological breakthrough, maybe in the fab process, that caused just a jump in the coherence times?
$endgroup$
– psitae
May 13 at 16:15
add a comment |
$begingroup$
So, to begin, I would point out that the 500 micosec T1 time is for a single qubit in isolation, while the GHZ results are on a 20 qubit device. This device has an avg T1 time of around ~75 microsec.
The GHZ results were done by Ken Wei from IBM, and will be published shortly.
In short, the circuit is a standard GHZ building circuit, with a hadamard gate followed by a chain of CNOT gates (As pictured above). These gates are ordered in such a way as to minimize the construction time by running CNOT gates in parallel on the device(not pictured above). Then there is a layer of phase gates (U1 gates in the IBM notation), followed by the reverse sequence of gates to undo the GHZ state. The U1 layer in the middle gives the states a phase that is then kicked-back in the unrolling at the end, and measured by the top qubit.
To make everything happen, you need high-fidelity CNOT gates, and high-fidelity parallel CNOT gates. In addition, and equally important, you need to be able to correct for measurement errors in the final result. Think of this as measurement tomography if you like. This is a part of the IBM Qiskit Ignis package (qiskit.org). Further details of how all this works together will be in the forthcoming publication
Update:
Here is the paper: Wei, Ken X., et al. "Verifying Multipartite Entangled GHZ States via Multiple Quantum Coherences" arXiv preprint arXiv:1905.05720 (2019).
edited May 15 at 13:30
Sanchayan Dutta
7,28741659
answered May 13 at 14:14
Paul NationPaul Nation
18613
$endgroup$
So, to begin, I would point out that the 500 micosec T1 time is for a single qubit in isolation, while the GHZ results are on a 20 qubit device. This device has an avg T1 time of around ~75 microsec.
The GHZ results were done by Ken Wei from IBM, and will be published shortly.
In short, the circuit is a standard GHZ building circuit, with a hadamard gate followed by a chain of CNOT gates (As pictured above). These gates are ordered in such a way as to minimize the construction time by running CNOT gates in parallel on the device(not pictured above). Then there is a layer of phase gates (U1 gates in the IBM notation), followed by the reverse sequence of gates to undo the GHZ state. The U1 layer in the middle gives the states a phase that is then kicked-back in the unrolling at the end, and measured by the top qubit.
To make everything happen, you need high-fidelity CNOT gates, and high-fidelity parallel CNOT gates. In addition, and equally important, you need to be able to correct for measurement errors in the final result. Think of this as measurement tomography if you like. This is a part of the IBM Qiskit Ignis package (qiskit.org). Further details of how all this works together will be in the forthcoming publication
Update:
Here is the paper: Wei, Ken X., et al. "Verifying Multipartite Entangled GHZ States via Multiple Quantum Coherences" arXiv preprint arXiv:1905.05720 (2019).
edited May 15 at 13:30
Sanchayan Dutta
7,28741659
answered May 13 at 14:14
Paul NationPaul Nation
18613
edited May 15 at 13:30
Sanchayan Dutta
7,28741659
edited May 15 at 13:30
Sanchayan Dutta
7,28741659
edited May 15 at 13:30
Sanchayan Dutta
7,28741659
7,28741659
answered May 13 at 14:14
Paul NationPaul Nation
18613
answered May 13 at 14:14
Paul NationPaul Nation
18613
answered May 13 at 14:14
Paul NationPaul Nation
18613
18613
2
$begingroup$
Hi Paul. You're clearly from the IBM group. It seems like careful calibration and the circuit above might be enough for the GHZ result. I'm quite impressed with the 500us coherence times too. Is there some technological breakthrough, maybe in the fab process, that caused just a jump in the coherence times?
$endgroup$
– psitae
May 13 at 16:15
add a comment |
2
$begingroup$
Hi Paul. You're clearly from the IBM group. It seems like careful calibration and the circuit above might be enough for the GHZ result. I'm quite impressed with the 500us coherence times too. Is there some technological breakthrough, maybe in the fab process, that caused just a jump in the coherence times?
$endgroup$
– psitae
May 13 at 16:15
2
2
$begingroup$
Hi Paul. You're clearly from the IBM group. It seems like careful calibration and the circuit above might be enough for the GHZ result. I'm quite impressed with the 500us coherence times too. Is there some technological breakthrough, maybe in the fab process, that caused just a jump in the coherence times?
$endgroup$
– psitae
May 13 at 16:15
$begingroup$
Hi Paul. You're clearly from the IBM group. It seems like careful calibration and the circuit above might be enough for the GHZ result. I'm quite impressed with the 500us coherence times too. Is there some technological breakthrough, maybe in the fab process, that caused just a jump in the coherence times?
$endgroup$
– psitae
May 13 at 16:15
add a comment |
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