# Questions tagged [qubo]

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### Grover Adaptive Search in Qiskit - why ancilla qubit is not used?

I am trying to solve some QUBO tasks with Grover Adaptive Search ("GAS"). For testing purposes, I use a simple task with quadratic part  A = \begin{pmatrix}0 & -0.5 \\ -0.5 & 0\end{...
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14 views

### qiskit vs dimod: ising matrix in 2 libaries are different

I have a simple QUBO problem in qiskit library: ...
• 111
34 views

### qiskit: convert from ising result to qubo result?

I have a very simple qubo problem: ...
• 111
1 vote
23 views

### How can a QUBO matrix with many identical, non-zero off-diagonal terms be made sparse?

I am with a QUBO matrix where entire off-diagonal sections are with the same value, which is the same between sections. Consider the following example (much smaller than those I am actually working ...
23 views

### QUBO formulation: tackle constraint with multiplication of two variables

Currently I have got the constraint like this $a+ab \leq1$ which can be reformulated to equality adding slack variable $(a+ab-1+slack)^2=0$. From now on, I can get all coefficients of the products ...
1 vote
80 views

### 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 & ...
42 views

### Find minimum eigenvalue of an Ising Hamiltonian combined with Error Mitigation

I am currently working on a variation of the Traveling Salesman Problem. For which I use the QUBO(Quadratic Unconstrained Binary Optimization). Within Qiskit there are potent functions to obtain the ...
56 views

### What are the important parameters when it comes to VQE algorithms in qiskit?

So I wrote an algorithm for a quadratic problem (qubo) and try to solve it. My question is why I don't get the correct results when running my algorithm on a quantum computer like IBM_manila. In the ...
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72 views

### 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 ...
51 views

### Mathematical definition of QUBO problem

The quantum annealing approach is using the equivalence between QUBO matrix and Ising Hamiltonian to solve the problem. Therefore, it is necessary to transform a NP-hard problem into a QUBO matrix. ...
65 views

### How to formulate QUBO as summation quadratic and linear parts of K-graph coloring problem?

While trying to understand the graph coloring problem with VQE using the QUBO Formulation mentioned section "5.2 Graph Coloring". Mentioned article prepared the QUBO directly in to matrix ...
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127 views

### 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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50 views

### Can any binary problem be solved by a QUBO?

As far as I know, if a computing problem can be solved by the quantum annealing approach, it also means the solution space should be binary, e.g., a vector that only contains either 0 and 1. Otherwise,...
118 views

### Correct implementation of Qiskit QAOA

I've been dealing with a QAOA implementation of a QUBO problem. In order to do this, I converted my QUBO matrix to a QuadraticModel. Once done, I have used ...
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