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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Usage of slack variables by Dimod (D-Wave)

I have a general question of the application of slack variables. For example, if I want to solve the following inequality: $x_{0}+x_{1}+x_{2}+x_{2} \leq 2$ Then I can reformulate the inequality above ...
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How are IBM's 127 qubits more potent than the 5760 qubits D-Wave - Advantage_system6.1?

Hi I'm a newbie in quantum computing recently I had a look at the AWS braket and I've seen they had a machine called D-Wave - Advantage_system6.1 that has 5760 qubits but when I googled the highest ...
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Help with objective function definition for CQM problem

I would like to set my problem as a constrained quadratic model (CQM), since a CQM allows users to explicitly define objective and constraints (easier for me, as I am not a QC expert!). The idea is to ...
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Conditioned quadratic model of variables

Using dimod.generators.combinations it is possible to generate a binary quadratic model that is minimized when k of n variables are selected. I'm trying to ...
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Convert Hamiltonian to Ising Formulation or QUBO

I have a tridiagonal Hamiltonian matrix that I need to convert to QUBO or Ising format to use D-Wave's quantum annealing solvers. For a generic tridiagonal: \begin{pmatrix} a_1 & b_1 \\ c_1 & ...
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Why do Quantum Annealer have (currently) a higher scaling potential?

One may categorize quantum computers in two classes: Quantum Annealer and (universal) Gate Quantum Computers. There may be also other categories. IBM announced 127 Qubits for their next Gate Quantum ...
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Penalty formulation regarding inequalitties

During the formulation of a QUBO matrix I have a question regarding penalty formulation. Once I'm done with QUBO formulation such as $x_{i}Ax_{j}$ where A is the QUBO matrix, $x_{i}$ and $x_{j}$ are ...
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Qubit fidelity of DWAVE device

Since DWAVE quantum device is constructed using superconducting flux qubits, each qubit cannot be produced identically so that the fidelity of the qubit must be different. DWAVE only provides the ...
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Is D-Wave advantage a noisier hardware compared to the older D-Wave 2000?

Is D-Wave Advantage noisier hardware compared to the older D-Wave 2000? There is any measure of the noise within the vendor's whitepapers, the quantum annealer analogue of e.g. decoherence time, ...
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Can D-Wave machines solve QUBO problems more efficiently than gate model devices?

I'm new to quantum annealing and D-Wave computer. I saw that it has about 5000 qubits which can solve a QUBO problem with 5000 variables. From my understanding, if we use a gate model device, say, an ...
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How do we calculate the offset in a QUBO formulation?

I am aware that for a quadratic optimization problem, we are required to minimize $y$ where $y = x^t Q x$ where $x$ is a column vector of binary variables and $Q$ is a QUBO matrix. I have the ...
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What is the role of Josephson junctions and biases in the D-Wave qubit structure?

On the D-Wave 2000Q there are up to 2048 qubits and 5600 coupler. A commonly used picture of one of such qubits is attached below. Each qubit is realized by a loop of niobium controlled by Josephson ...
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What should be the lowest energy of this graph isomorphism QUBO?

I am trying to study QUBO formulations of the graph isomorphism problem. I tried implementing the QUBO matrices given by the algorithms described in here. For the two input graphs therein, I am ...
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Sampling from a given Boltzmann distribution using D-Wave systems

For a project I'm working on, I want to use D-Wave systems to estimate the probabilities of a Boltzmann distribution given a QUBO (Hamiltonian), this being performed through sampling and the use of ...
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From general Hamiltonian to Ising Hamiltonian

I would like to convert my qubit hamiltonian fom the HeH+ system that I have obtained using Qiskit to an Ising or QUBO model. I have seen multiples examples from QUBO to Qubit Hamiltonian but on the ...
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How is eigendecomposition of a Hamiltonian equivalent to finding the minimum of an energy function?

This question is in regards to Dwave's quantum computer which is tailored to solve QUBO problems using quantum annealing. QM tells us that the ground state of a quantum system is given by the ...
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The Adiabatic Theorem - How to derive Schrödinger equation in the "s" variable

I'm studying Adiabatic Quantum computing from the book "Adiabatic Quantum Computation and Quantum Annealing: Theory and Practice" by Catherine C. McGeoch at D-Wave. The section THE ...
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Output of D-Wave LeapHybrid solver takes long to evaluate

we made the strange observation that the evaluation of the output in form of the dimod.SampleSet takes a long time to evaluate especially in comparison to the actual sampling step. Here is a minimal ...
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How to improve embedding process in D-Wave?

I am quite new to the quantum computing field. Currently, I am trying to solve a combinatorial optimization problem on a D-Wave system, which I successfully translated into QUBO form. I also managed ...
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What do the numbers in the Ising sampleset mean?

I am trying to create a portfolio optimization with the DWave Quantum Computer. I wrote some code trying to somehow reconstruct the following Ising model paper: Ai ...
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What is the state-of-the-art annealing device for solving Ising problems?

I understand that in addition to D-Wave's quantum annealer, there have been other unconventional (although non-quantum) Ising solvers like the one from Toshiba, Fujitsu, the Coherent Ising machine, ...
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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. By inequality, I mean something like this: 0⩽ Expression ⩽ N. We can introduce a slack variable and convert it to an equality problem: ⟹ ...
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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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2 answers
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The commutation relation $[H_d, \sum_{i = 1}^n \sigma_i^z] = 0$ from the paper about the constrained quantum annealing (CQA)

A quote from the paper "Quantum annealing for constrained optimization" by I. Hen, F. M. Spedalieri: Let us now consider the driver Hamiltonian $$H_d = - \sum_{i=1}^n \left( \sigma_i^x \...
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Moore's law for quantum computers

Moore's law states that performance of classical computers doubles every two years (later revised to 18 months) and a price for computing resources halves during same time period. Currently, it seems ...
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How do IBM, D-Wave, etc. change phase physically?

How do IBM, D-Wave, etc. change phase physically? In real hardware?
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What is an example of a simple QUBO problem?

I am digging into to the workings of the D-wave quantum annealing computers using this documentation. I find it very intuitive and well-explained, but their example of a "simple QUBO problem" does not ...
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8 votes
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Is there quantum advantage to be had with a D-Wave computer in 2020?

I've seen a lot of excitement in the popular press about the computers made by D-Wave Systems, but when I dig deep the only practical things that I can figure out that one can do with the computer are ...
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How qubit phase is build in real hardware?

How qubit phase is build in real hardware? On IBM Quantum, D-Wave, etc?
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Quantum Annealing - Random results on big N

I implemented a solver for the Job Shop Problem, based on quantum annealing, on a D-Wave machine. I have a problem, that even though minimal energy solutions exist, they are only chosen once. I set ...
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Is it possible to use D-Wave systems for free?

IBM offers its platform IBM Q for free with certain constraints, such as available quantum processors and number of jobs running in parallel. I was wondering whether there is the same possibility on ...
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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 ...
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2 votes
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Quantum Annealing - Job Shop Problem

using this paper, I want to implement a solution for the Job Shop Problem on a D-Wave machine. One of the constraints mentioned in the paper, is $$ h_3(\bar{x}) = \sum_i \left(\sum_t x_{i,t}-1 \right)^...
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3 votes
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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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4 votes
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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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5 votes
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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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6 votes
1 answer
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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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2 votes
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What is the "TRIAD" graph and where can I find more information about it?

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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5 votes
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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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