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32 votes

Which subatomic particle does each company use in quantum computing?

Google, IBM and Rigetti use transmon qubits; these are basically fancy LC circuits where a Josephson junction and capacitor connect two superconducting islands. Because of this, they are also often ...
JSdJ's user avatar
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30 votes
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Is there proof that the D-wave (one) is a quantum computer and is effective?

There is still a search for problems where the D-Wave shows improvement over classical algorithms. One might recall media splashes where the D-Wave solved some instances $10^8$ times faster than a ...
Andrew O's user avatar
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28 votes
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How do you write a simple program for a D-Wave device?

The 'Hello World' equivalent in the D-Wave world is the 2D checkerboard example. In this example, you are given the following square graph with 4 nodes:        &...
Mark Fingerhuth's user avatar
23 votes
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Did D-Wave show quantum advantage in 2023?

A clear case of quantum advantage Google's quantum group demonstrated quantum advantage with a much earlier version of D-Wave hardware in the following figure from a 2016 paper, in which the D-Wave ...
user1271772 No more free time's user avatar
19 votes
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Why can't quantum annealing be described by a gate model?

A Quantum Annealer, such as a D-Wave machine is a physical representation of the Ising model and as such has a 'problem' Hamiltonian of the form $$H_P = \sum_{J=1}^nh_j\sigma_j^z + \sum_{i, j}J_{ij}\...
Mithrandir24601's user avatar
  • 3,716
17 votes

Why can't quantum annealing be described by a gate model?

Annealing's more of an analog tactic. The gist is that you have some weird function that you want to optimize. So, you bounce around it. At first, the "temperature" is very high, such that the ...
Nat's user avatar
  • 1,497
11 votes

Is Google's 72 qubit device better than D-Wave's machines, which feature more than 2000 qubits?

There are two points I'd make here. D-Wave's computer and Google's computer are fundamentally different. D-Wave's computer is a quantum annealer. Imagine a landscape with some grassy hills. If you put ...
auden's user avatar
  • 3,459
11 votes
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Is Google's 72 qubit device better than D-Wave's machines, which feature more than 2000 qubits?

Short explanation: D-Wave implements quantum annealing, while Google has digitized adiabatic quantum computation. Lengthy Explanation: D-Wave advertises their line of quantum computers as having ...
Rob's user avatar
  • 2,327
10 votes
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How much faster is “D-Wave Two” compared to its predecessor?

As Troyer and Lidar saw no speed increase with the D-Wave 1 compared to classical computers, the D-Wave 2 benchmark figure reported in 2013 of 3600 times as fast as CPLEX (the best algorithm on a ...
Rory Alsop's user avatar
10 votes
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How are IBM's 127 qubits more potent than the 5760 qubits D-Wave - Advantage_system6.1?

They are different kinds of quantum computers: The D-Wave is a quantum Annealer. A rather specific (non-general purpose) device that can solve QUBO-type problems. IBM offers universal gate-based ...
quantum's user avatar
  • 585
9 votes

Is there proof that the D-wave (one) is a quantum computer and is effective?

Is there proof that the D-wave (one) is a quantum computer and is effective? D-Wave Video - Offers an explanation of: "How do we know ...": https://youtu.be/kq9VqR0ZGNc One analogy you might make ...
Rob's user avatar
  • 2,327
9 votes

How do you write a simple program for a D-Wave device?

The title and question body seem to ask two different questions. In the title you ask "How do you write a simple program for a D-Wave device?", while in the question body you ask how to find the ...
Sanchayan Dutta's user avatar
8 votes
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How to explain in layman’s terms the significance of the difference of qubits of the D-Wave and IBM QX?

In the classical case, there is a pretty big difference between digital computers and analogue ones. The methodology and hardware is very much distinct (in all cases I know of, at least). The divide ...
James Wootton's user avatar
8 votes

What are XX, YY, YZ etc. couplings?

In the mentioned context, what is meant is that, between a pair of qubits that are coupled, an XX coupling means something of the form $$ X\otimes X\equiv\left(\begin{array}{cccc} 0 & 0 & 0 &...
DaftWullie's user avatar
  • 59.2k
7 votes

How much faster is “D-Wave Two” compared to its predecessor?

As far as I know the closest answer to your question for applications is given in the recent (still unpublished) work presented at the March meeting by Bibek Pokharel, where he compares graph 3-...
Davide Venturelli's user avatar
7 votes
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Is it important for a quantum computer to be shielded by the magnetic field?

The DWave machine relies heavily on single-flux-quantum digital control for setting up qubit and coupler operating points, and for carrying out the annealing protocol. Any stray magnetic flux, if ...
Ofer Naaman's user avatar
7 votes
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Why D-Wave 2000Q requires such a low pressure?

Pressure implies the presence of stray atoms flying around messing things up. The use of a vacuum is required to prevent this, as one of the ways of keeping the device well isolated from unwanted ...
James Wootton's user avatar
7 votes

How would D-Wave be used for complex optimization problems?

So I do not know much about yacht design but having played a little bit with a D-Wave machine I would suggest to see if you can model your problem as a Quadratic unconstrained binary optimization. See ...
cnada's user avatar
  • 4,754
7 votes

How are IBM's 127 qubits more potent than the 5760 qubits D-Wave - Advantage_system6.1?

As the other answers have stated, they're two substantially different systems that are unfortunately both marketed as quantum computers. D-Wave is more specifically a quantum annealer. At a high level,...
Chris E's user avatar
  • 1,438
7 votes

Does the D-Wave hardware show any advantage for academic use-cases, for example in condensed matter physics?

Interest in academia In the past, only a small number of academic institutions, with a small number of professors, existed. Now there's about 30,000 universities and who knows how many colleges, ...
user1271772 No more free time's user avatar
6 votes

How do you write a simple program for a D-Wave device?

The inputs to the D-Wave are a list of interactions and more recently the annealing time of the qubits. As you mentioned the Ising problem is one of the easiest with $J_{ij} = 1$ in the problem ...
Andrew O's user avatar
  • 1,749
5 votes

What is D-Wave's "Pegasus" architecture?

Pegasus is the first fundamental change in D-Wave's architecture since the D-Wave One. The D-Wave Two, 2X, and 2000Q all used the "Chimera" architecture, which consisted of unit cells of $K_{4,4}$ ...
user1271772 No more free time's user avatar
5 votes

Why D-Wave 2000Q requires such a low pressure?

The device works at cryogenic temperatures, which is so cold that all the gasses would freeze on the experiment device. Moreover, before they do so, they would conduct heat from the walls of the ...
Johu's user avatar
  • 201
5 votes
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What would be the simplest addition that would make the D-Wave architecture universal?

XX couplers are necessary to make an quantum annealing universal. https://arxiv.org/abs/0704.1287 As for fabricating them, I’m not too familiar with the hardware issues. Perhaps someone else can ...
Andrew O's user avatar
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5 votes
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What precisely is Reverse Annealing?

Until recently, D-Wave's quantum annealing devices always started from a uniform superposition over all $N$ qubits:               ...
Mark Fingerhuth's user avatar
5 votes
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When and where was the first use of the term Chimera?

The earliest non-internal reference I can find is in NIPS 2009 from a Google/D-Wave effort1. You'll notice that the two Choi papers, in addition to not using the term "Chimera", do not describe a ...
Andrew D. King's user avatar
5 votes

D-Wave systems and IBM Q System One

When referring to the commercial quantum computers of both parties, it is that both are based on a different quantum principles. The D-Wave machine works via quantum annealing and is suited for ...
nippon's user avatar
  • 1,517
5 votes
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What is the problem in demonstrating quantum supremacy?

D-Wave's 2000Q is a quantum annealer, not a circuit-based quantum computer like Google's Sycamore. The qubits in D-Wave's system are much noisier, less controlled and perform a fundamentally ...
Jonathan Trousdale's user avatar
5 votes
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Moore's law for quantum computers

Moore's law deals with the number of transistors in an integrated circuit, which is used as a proxy for computational power. In a quantum computing device the analogy would be the number of qubits. ...
Paul Nation's user avatar
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