Questions tagged [google-sycamore]

A 54-qubit superconducting quantum processor by Google Quantum AI which is claimed to have been used to demonstrate quantum computational supremacy.

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What does Google's claim of “Quantum Supremacy” mean for the question of BQP vs BPP vs NP?

Google recently announced that they have achieved "Quantum Supremacy": "that would be practically impossible for a classical machine." Does this mean that they have definitely proved that BQP ≠ BPP ?...
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1answer
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Which subatomic particle does each company use in quantum computing?

Probably each company (Google, Amazon, Intel, IBM, Microsoft, D-Wave and so on) uses a mix of subatomic particles and technologies. I would like to know which particles/technologies are used by each ...
11
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3answers
420 views

Why do the IBM and Google processors both have 53 qubits?

As I understand from this IBM post both the IBM and Google teams have independently built 53-qubit processors. What is the significance of the number 53? It is purely coincidental, or is there a ...
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575 views

Understanding Google's “Quantum supremacy using a programmable superconducting processor” (Part 1): choice of gate set

I was recently going through the paper titled "Quantum supremacy using a programmable superconducting processor" by NASA Ames Research Centre and the Google Quantum AI team (note that the paper was ...
7
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1answer
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Are 20 repetitions of Sycamore's one- and 2-qubit gates sufficient to produce a uniformly random state?

In the answer to this question about random circuits, James Wootton states: One way to see how well we [fully explore the Hilbert space] is to focus on just randomly producing $n$ qubit states. ...
7
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1answer
269 views

Why does Google's quantum processor outperform IBM's?

I understand that both have 53 qubit devices, yet it is Google that has demonstrated quantum supremacy (although IBM refutes this!). I'm not sure if this is true but it seems like IBM cannot replicate ...
6
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1answer
505 views

Understanding Google's “Quantum supremacy using a programmable superconducting processor” (Part 2): simplifiable and intractable tilings

In Google's 54 qubit Sycamore processor, they created a 53 qubit quantum circuit using a random selection of gates from the set $\{\sqrt{X}, \sqrt{Y}, \sqrt{W}\}$ in the following pattern: ...
6
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1answer
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What did exactly Google do in simulating a random quantum circuit on a classical computer in supremacy experiment?

I've been working on Google quantum supremacy paper for quite some time now and I have a problem in understanding how exactly they simulate their actual random quantum circuit on a classical computer. ...
6
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1answer
229 views

Number of qubits to achieve quantum supremacy?

Google's Sycamore paper describes achieving quantum supremacy on a $53$-qubit quantum computer. The layout of Sycamore is $n=6\times 9=54$ nearest neighbors, with one qubit nonfunctional. They apply ...
5
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3answers
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Quantum Supremacy: Some questions on cross-entropy benchmarking

I was skimming through the Google quantum supremacy paper but got stuck on this section: For a given circuit, we collect the measured bit-strings $\{x_i\}$ and compute the linear XEB fidelity [24-26, ...
5
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1answer
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Why Google has used $\sqrt{X}$ and $\sqrt{Y}$ instead of $X$ and $Y$ in supremacy experiment?

In supremacy experiment Google has used $\sqrt{X}$ and $\sqrt{Y}$ as two of their single qubit gates (paper). So My questions are: Is there any specific reason for choosing these gates and not $X$...
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1answer
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Understanding Google's “Quantum supremacy using a programmable superconducting processor” (Part 3): sampling

In Google's 54 qubit Sycamore processor, they created a 53 qubit quantum circuit using a random selection of gates from the set $\{\sqrt{X}, \sqrt{Y}, \sqrt{W}\}$ in the following pattern: ...
4
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2answers
200 views

Location of “bad” qubits on Sycamore

The Sycamore paper from Google notes that Sycamore is a $54$-qubit quantum processor, but for their experiments only $53$ qubits were working. The "bad" qubit was on the edge of the array. Is ...
3
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2answers
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How exactly is solving the random circuit sampling problem a computation in the Church-Turing thesis sense?

Note: This has been cross-posted to CS Theory SE. If we assume $\mathsf{BQP} \neq \mathsf{BPP}$, then we can say with reasonable certainty that Google's random sampling experiment falsifies the ...
3
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1answer
429 views

Making sense of the Sycamore's computing prowess - power consumption

I came here after reading about the announcement regarding the Sycamore processor and Google's Quantum Supremacy claim. I am hung up on several key things and I am hoping that I could find those ...
3
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2answers
277 views

Do quantum supremacy experiments repeatedly apply the same random unitary?

It is my understanding that, given a quantum computer with $n$ qubits and a way to apply $m$ single- and 2-qubit gates, quantum supremacy experiments Initialize the $n$ qubits into the all-zero's ket ...
3
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1answer
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Where are the physical gates in the Google processor?

Google's article Quantum supremacy using a programmable superconducting processor states that the processor "53 qubits, 1,113 single-qubit gates, 430 two-qubit gates, and a measurement on each qubit, ...
3
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1answer
124 views

Can we conclude that errors on Sycamore are Poisson-distributed Pauli errors?

In Martinis' recent Caltech lecture on the Sycamore paper, he appears to make much of the fact that FIG. 4 of the paper show straight-line fidelity - that is, the fidelity decreases log-linearly with ...
3
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1answer
59 views

What is the role of choosing the single-qubits randomly in Google quantum supremacy experiment?

In supremacy paper and part D of section VII of supplementary information (below), it is said that there is a pseudo-random number generator that is initialized with a seed called $s$; And then the ...
2
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1answer
77 views

Do all physical architectures for quantum computers use the same universal gate sets?

Now I have understood that physical implementation of quantum computer need a universal quantum gate set like Clifford+T to realize any unitary quantum gate. However, I don't know if it is all the ...
2
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1answer
42 views

In Google's Quantum Supremacy experiment, what if we use $\theta=45°$ for two-qubit $f_{sim}$ gates?

In Google's Quantum Supremacy experiment, they use $f_{sim}$(fermionic-simulation) gates with $\theta=90°$ and $\phi=30°$ as their two-qubit gates. What if we use $\theta=45°$ for the two-qubit $f_{...