# Questions tagged [d-wave]

A quantum computing company, based in Burnaby, British Columbia, Canada, mostly known for their quantum annealing computers. An early rendition of these, D-Wave One, was the first commercially available quantum computer. (Wikipedia)

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### How to decide bias in Hamiltonian Ising model?

I am trying to code finance portfolio optimisation problem into a quantum annealer, using the Hamiltonian Ising model. I am using the dwave module ...
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### Why is it so important to have uniform chain lengths in a minor embedding?

Very brief background In quantum annealing, the discrete optimization problem we wish to solve (such as finding the minimum of $b_1b_2 - 3b_1 + 5b_3b_4$ for binary variables $b_i$) may have a ...
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### From Qiskit QuadraticProgram to problem model accepted by d'wave ocean

Is there a way to convert QuadraticProgram (qiskit.optimization.problems.QuadraticProgram) to BQM used in D'wave ocean (e.g. <...
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### What is the computational complexity of quantum annealing?

Quantum annealing can be thought of as a black box solver that can find approximate solutions to hard optimization problems. For example, D-Wave quantum annealers can approximately solve quadratic ...
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### Inequality constraints on D'Wave (using PyQUBO)

Inequalities cannot be directly converted into a qubo form 0⩽ Expression ⩽ N We can introduce a slack variable and convert it to an equality problem: ⟹ Expression + s = N where: s ∈ Z, s ∈ [0,N] Since ...
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### D-WAVE QUBO Matrix Form

I am trying to write down this problem (friend/enemy graph) in a polynomial matrix form in order to understand quantum annealing better, but it seems like the problem should actually be split into ...
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### What is the query complexity of the QUBO algorithm?

What is the complexity of the quantum unconstrained binary optimization (QUBO) algorithm in the number of queries to the quantum processor? To clarify, I'm asking about the complexity on quantum ...
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### What is the problem in demonstrating quantum supremacy?

I am new to the quantum world and it's computing. But it accidentally hit in my mind that DWave built a quantum computer with 2000 qubits which can be use to simulate the whole observable universe or ...
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### Suggestions for hybrid factoring algorithm on DWave and Qiskit

I was wondering if the multi-prime factoring problem can be solved in a hybrid approach using DWave (to factor) and Shor's algorithm (in Qiskit)? Please let me know your thoughts. Thanks!
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### How to get samples in “bins” from D-Wave's dimod?

at 1, the following code example is available: ...
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### Minimum Spanning Tree on D Wave Processor

I am attempting to implement a minimum spanning tree problem on the D wave quantum computing architecture. I have seen many graph problems implemented, such as a graph coloring example. There are also ...
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### What does it mean to have 2000 qubits and 6016 couplers?

From official D-Wave docs: The D-Wave 2000Q QPU has up to 2048 qubits and 6016 couplers. For example, I have the optimization problem defined as the QUBO problem. If I want to solve it on D-Wave,...
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### How to calculate the $r^{\text{th}}$ digit of $\sum ^{j−1}_{p=i}d^p_{\pm k}$ using PyQUBO?

I am going to implement "turn circuit encoding" method of Coarse-grained lattice protein folding on a quantum annealer(Babej, Ing & Fingerhuth; 2018) using PyQUBO to run on the DWave qbsolv ...
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### D-Wave systems and IBM Q System One

What is the difference between the D-Wave systems and the newly-born IBM Q System One?
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### What are techniques are used to esimate the spectral properties of annealer embedding hamiltonians?

Some information about the spectral properties of the hamiltonian of a given annealer emebedding is needed to determine a proper annealing schedule, correct? What are methods that are used to find ...
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### Are there established best practices for designing Dwave embeddings?

Some of my larger annealer embeddings (~200 qubits) don't anneal down to the ground state while some of them do very easily. Are there established guidelines for designing annealer embeddings to ...
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### What are XX, YY, YZ etc. couplings?

The D-wave quantum computer allows us to be able to minimize Ising models. In reading other questions and responses, particularly What would be the simplest addition that would make the D-Wave ...
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I was looking up how to program for a D-Wave machine and I came across this image which says it's the "optimal hardware graph" for a D-Wave machine: Unfortunately the image seems to have come from ...
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### When and where was the first use of the term Chimera?

This is along the same lines as the earlier question: When was the first use of the word Entanglement? I was surprised to discover that when searching for "chimera" in both of Vicky Choi's minor-...
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### Does the D-Wave 2000Q satisfy DiVincenzo's criteria?

DiVincenzo's criteria for quantum computation are the following: A scalable physical system with well characterized qubits. The ability to initialize the state of the qubits to a simple fiducial ...
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### What's a Qubit on D-Wave 2000Q?

From D-Wave flyer: The D-Wave 2000Q system has up to 2048 qubits and 5600 couplers. To reach this scale, it uses 128,000 Josephson junctions, which makes the D-Wave 2000Q QPU by far the most ...
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### In D-Wave's universal quantum computer, why does the YY term have to be driven along with the linear X term?

D-Wave has a new prototype annealer that uses a Hamiltonian which, if there was enough qubits and sufficient control, would be able to simulate any universal circuit-based quantum computer with at ...
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### How would D-Wave be used for complex optimization problems? [closed]

We are interested in solving an optimization problem, and specifically, the design of efficient yacht hulls. In designing an efficient yacht hull, one must consider water-hull resistance, wave ...
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### What methods exist for cooling superconducting quantum computers? [duplicate]

Existing superconducting quantum computers need to be cooled near absolute zero. For example, some of D-Wave's machines are cooled to about $20 \ \mathrm {mK}$. Their design uses a dilution ...
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### What is D-Wave's “Pegasus” architecture?

How is D-Wave's Pegasus architecture different from the Chimera architecture?
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### Why did D-Wave choose the Chimera graph the way they did?

D-Wave makes use of a $(n,k=4)$-Chimera structured graph in their computers. Meaning a $n\times n$ grid of unit cells, with each unit cell consisting of a complete bipartite graph on $2k=8$ nodes ($4$ ...
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### What precisely is Reverse Annealing?

Quantum Annealing, (related questions Quantum Annealing, or hamiltonian related) is the process used in D-Waves' Quantum Annealer, in which the energy landscapes are explored, for different solutions, ...
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### Requirements for Achieving a Quantum Speedup

We usually talk about the power of a quantum computer by examining the separation between sets of gates that we know we can efficiently simulate on a classical computer (i.e. problems in the class BPP)...
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### What would be the simplest addition that would make the D-Wave architecture universal?

The D-Wave system, as I understand it, allows us to program Ising models and to find their ground states. In this form, it is not universal for quantum computation: it can not simulate a circuit model ...
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### How can a D-Wave style Annealing QPU help sampling?

This question is a follow-up on this one, with the hope of getting more specific clues, and was motivated by this answer by user Rob. Also please note this posts that handle the topic of QA in much ...
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### Do the latest D-Wave computers use Helium compounds for cooling?

Do the latest D-Wave machines use compounds of $\require{\mhchem}\ce{^{3}He}$ and $\ce{^{4}He}$ for cooling? If not, how does D-Wave approach cooling its plates low enough to achieve superconductivity?...
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### Why D-Wave 2000Q requires such a low pressure?

On the D-Wave 2000Q website, it is stated that the processor environment is kept "in a high vacuum: pressure is 10 billion times lower than atmospheric pressure". Why the pressure has to be such low? ...
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### How do you write a simple program for a D-Wave device?

I would like to know how a job for a D-Wave device is written in code and submitted to the device. In the answer it would be best to see a specific example of this for a simple problem. I guess that ...
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### Hardware wise, how does D-Wave achieve quantum annealing?

Quantum computers have shown a new way to compute old problems. D-Wave has a quantum annealer, and Wikipedia describes the D-Wave quantum computer and its use of quantum annealing properties. ...
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### Is it important for a quantum computer to be shielded by the magnetic field?

I've been browsing The D-Wave 2000Q site when I bumped into this aspect of their quantum computers: A Unique Processor Environment Shielded to 50,000× less than Earth’s magnetic field Why is that ...
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### Is Google's 72 qubit device better than D-Wave's machines, which feature more than 2000 qubits? [duplicate]

Google recently announced the Bristlecone 72 qubit quantum computer. However, D-Wave already announced quantum computers featuring more than $2000$ qubits. Why is Google's new device newsworthy then? ...
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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?

So, @AndrewO mentioned recently that he has had 'encounters' with people wondering why D-Wave has a lot more qubits than IBM. Of course, this comparison is faulty, since the IBM and D-Wave's machine ...
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### Is there proof that the D-wave (one) is a quantum computer and is effective?

I'm admittedly a novice in this field, but I have read that, while the D-wave (one) is an interesting device, there is some skepticism regarding it being 1) useful and 2) actually a 'quantum computer'....