Questions tagged [qaoa]

For questions about the Quantum Approximate Optimization Algorithm (QAOA), first introduced in Farhi, Goldstone, Gutmann 2014 (https://arxiv.org/abs/1411.4028).

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3 votes
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qiskit QAOA on Aer GPU giving errors

I am trying to run Qiskit QAOA algorithm on using aer simulator and device GPU. But I am not sure how to give this backend in the QAOA algorithm structure. Here is ...
1 vote
1 answer
30 views

Mapping a QUBO onto an observable for use with Qiskit QAOA

Background I am attempting to understand the post-aqua way that external qiskit libraries are supposed to be used for solving QUBOs. To do so I am trying to work with the toy problem of minimizing $f(...
3 votes
0 answers
40 views

How to update angles

I am struggling to understand the concept of updating angles in a parameterized algorithm. Assume I have an objective function $x^2+1$ that I want to optimize using QAOA which can handle continuous ...
4 votes
1 answer
272 views

Qiskit unable to transpile the circuit for Rigetti Aspen M 1 on AWS

I am trying to run a Qiskit QAOA algorithm on AWS Rigetti Aspen M 1 Backend using qiskit braket provider. However qiskit is not able to properly transpile the circuit ...
3 votes
0 answers
27 views

Retrieving job result attributes in Qiskit

I am trying to optimize a Hamiltonian using QAOA in IBM Qiskit. I used the following 'minimize' function to get my result. (I am not including the whole code because it will get unnecessarily long). <...
3 votes
0 answers
26 views

How can one use QAOA to obtain parameters that approximate the first excited state of the target Hamiltonian?

One can use QAOA to find the ground state and its energy by minimizing the expectation value of a target Hamiltonian (say, $H_T$) with respect to the QAOA ansatz and obtaining optimal parameters ...
2 votes
1 answer
55 views

Qiskit qubit ordering

In their to_ising documantation page, Qiskit devs mark the comment: Variables are mapped to qubits in the same order, i.e., $i$-th variable is mapped to $i$-th ...
1 vote
1 answer
102 views

Calculating state fidelity and space complexity of Minimum Eigen Optimizers (VQE, QAOA and Grover Optimizer) in qiskit

I'm a beginner in using Qiskit and my Computer Science background is not extensive. But I understand the Quantum Physics aspects of it relatively well. I solved a QUBO problem in Qiskit using VQE (...
1 vote
1 answer
46 views

How are edge weights "loaded" in the problem hamiltonian when solving TSP with QAOA?

I've come across several of the QAOA tutorials, and yet I'm afraid I haven't found any explanation on this. According to the Qiskit tutorial on QAOA, the cost function for the target problem has a ...
3 votes
1 answer
391 views

QUBO defined in Qiskit/DOcplex: how to solve it using Pennylane?

I have a complex Integer Linear Programming model defined in DOcplex/Qiskit representing a combinatorial optimization problem. Using the Qiskit utils, it is possible to covert it to either an Ising ...
1 vote
0 answers
75 views

Converting Ising Hamiltonian to a Circuit in Qiskit

I tried to solve a 2-node TSP (travelling salesman problem) by implementing QAOA on Qiskit. The graph looks like: Then I used the related Qiskit functions to convert the graph to the QUBO and map it ...
0 votes
1 answer
175 views

Implementation of QAOA to solve version of knapsack problem

Say I want to fill a knapsack with as many things as possible. I don't care about what they are, simply the number. But I don't want the total weight to exceed a set limit. [https://qiskit.org/...
1 vote
0 answers
55 views

Building a problem unitary circuit for QAOA on Qiskit

I am trying to build a circuit for QAOA that solves a Traveling Salesman's Problem, which can be represented as a complete graph with 4 nodes. After formulating the problem as a QUBO and mapping it ...
4 votes
0 answers
93 views

Qiskit QAOA optimization does not work when setting simulation seed in AerSampler

I am using Qiskit's QAOA for optimization and I would like to extract the probabilities distribution obtained in the optimization loop when running the circuit with the optimal parameters set. To do ...
1 vote
1 answer
211 views

QAOA Optimization

I want to use historical data for 5 stocks from YahooFinance and then calculate mean vector and covariance matrice, so I can optimize them with QAOA. Anyone know what is wrong with this code:
7 votes
2 answers
161 views

Quantum annealing - studies showing empirical evidence for better performance in comparison with classical computers

Currently, it is not known wheter quantum anneling or algorithms like VQE and QAOA for general purpose quantum computers bring about any increase in computational power. However, there are some ...
5 votes
1 answer
92 views

Recent experimental demonstrations of variational quantum algorithms?

I am interested in the recent experimental demonstrations of variational quantum algorithms. Can someone please provide me with a list of references of recent experimental demonstrations of ...
2 votes
0 answers
37 views

Implementing Adiabatic Grover Search via QAOA

I am reading the paper Grover Search Inspired Alternating Operator Ansatz of Quantum Approximate Optimization Algorithm for Search Problems. The paper proposes running the Adiabatic Grover Search ...
1 vote
0 answers
76 views

IS my QUBO too big for QAOA using IBM Quantum computer?

On qiskit, I have defined a QUBO, called qp as follows: ...
1 vote
1 answer
83 views

QAOA on weighted graphs

I tried to use the QAOA to solve the MaxCut problem on a 10 nodes weighted graph and run the simulation on qiskit from $p = 1$ to $p = 6$. I was expecting to get closer to the real solution as $p$ ...
1 vote
0 answers
48 views

Link between AQC and QAOA

I try to understand precisely the link between AQC and QAOA, through the Trotter-Suzuki formula. A similar question is Derivation of QAOA from AQC, but I was asked by moderators to post my question ...
4 votes
1 answer
200 views

Derivation of QAOA from AQC

In adiabatic quantum optimization we start with an initial Hamiltonian $H_0$ and then adiabatically evolve from $H_0$ to $H_P$ (problem hamiltonian) for a time $T$ according to \begin{equation}\label{...
1 vote
1 answer
47 views

How to add a circuit layer after computing QAOA layer

I have used the Qiskit-based QAOA function to solve a combinatorial problem tsp, and I want to append a circuit after the QAOA layer, is there any way to do that? Qaoa
0 votes
0 answers
30 views

How to tune QAOAAnsatz when solution is known to have a certain form?

I'm running QAOAAnsatz in QisKit, and I know that the solution to my problem has a certain form. Namely: ...
5 votes
0 answers
99 views

How to use Warm-Start QAOA in QisKit to solve non-convex QUBO problem?

I have a non-convex QUBO problem that I'd like to solve by warm-starting QAOA with a solution obtained from a continuous relaxation solution obtained by a classical algorithm. The specifics of the ...
1 vote
0 answers
40 views

'Continuous' (Classical) Cost function for QAOA

I have some combinatorial optimization problems which I would like to analyze using QAOA. These problems are coming from various applications in scientific computing such as solving PDEs. Some of ...
1 vote
0 answers
79 views

QAOA algorithm from qiskit.algorithms.minimum_eigensolvers sends jobs without stopping

I don't know why the code keeps sending jobs. The code is: ...
0 votes
1 answer
72 views

Portfolio optimization via quantum Zeno dynamics in Qiskit

Recently, I came across paper Portfolio Optimization via Quantum Zeno Dynamics on a Quantum Processor. In the paper, a new approach to optimization with QAOA is introduced. Instead of employing a ...
0 votes
2 answers
129 views

How to get angles optimized by classical optimizer from QisKit's QAOA Module?

I have the following simple optimization in QAOA: ...
3 votes
1 answer
59 views

How to sanity check QAOA cost Hamiltonian?

I'm trying to learn QAOA and how to apply it to a complex combinatorial problem. But for the purpose of this question I'll use the common example MaxCut. I'd like to know if I've set up my cost ...
3 votes
2 answers
247 views

Does QAOA require that the problem Hamiltonian be an Ising Hamiltonian as a quadratic function of the spin variables?

In the context of QAOA, I often see the problem Hamiltonian being called an "Ising Hamiltonian", and shortly after, I that the Hamiltonian is a quadratic function of the spin variables. Is ...
2 votes
0 answers
40 views

Can we easily find the ground states for one-dimensional ANNNI-like Ising models?

The Hamiltonian for a simple one-dimensional Ising model on a finite (linear) chain of $L$ spin-half particles might be: $$H = -J \sum_{i=0}^{L-1} \sigma_i^z \sigma_{i+1}^z.\tag{1}$$ The interactions ...
3 votes
1 answer
143 views

Does QAO Ansatz have any better performance guarantees than QAOA?

QAOA is a well-known heuristic for solving optimization problems, and it has the desirable property that as p -> infinity, the true minimum objective function value is reached. There is a ...
0 votes
0 answers
107 views

Combinatorial optimization problems solving using VQE

I'm studying about the variational quantum algorithms and I would like to know about the usage of VQE for solving combinatorial optimization problems. VQE can find the ground state energy of a given ...
4 votes
0 answers
126 views

Probability inequality for Quantum Approximate Optimization Algorithm (QAOA)

In arXiv:2207.14734 the authors claim that it is "straightforward to show that" their equation 8 holds: $$\mathrm{Pr}_{x\sim q}[x:f(x)\geq \mu] \geq \frac{1}{M}$$ where we have an objective ...
0 votes
0 answers
46 views

Variational Quantum Algorithms for Graph Traversal

I have a combinatorial optimization problem which on a first pass I think boils down to finding a path with a maximal score. The score for a path is computed by an auxiliary function. Are there near-...
0 votes
0 answers
23 views

Maximize the Sum of absolut Vector elements with QAOA

Im trying to get started with QAOA. I tried to program a simple example for testing my understanding. The goal is to maximize $z^TV$ with $V \in \mathbb{R}^{nx1},z \in ${$-1,1$}$^n$. I tried ...
0 votes
1 answer
70 views

Using BFGS for MAXCUT

In the original Qiskit QAOA implementation, the sample uses COBYLA as the classical optimizer in the following code segment: ...
1 vote
0 answers
45 views

Qiskit: The parameters of the circuits constructed by QAOAAnsatz will change after decomposition and transpilation

When I submit a parametrized circuit as an input for the mixed operator in QAOAAnsatz, some strange results appear. For example, when I submit a parametrized ...
2 votes
0 answers
74 views

Custom Mixer for QAOA for Graph Coloring, where to start?

I am trying to implement QAOA for graph coloring with hard constraints. In this paper, eq. 9 a custom mixer is proposed, is looks like this: $B_{ui} = \frac{1}{2^{l + 1}}(X_{u0}X_{u1} + Y_{u0}Y_{u1}) \...
1 vote
0 answers
71 views

Applying horizontal dots in a LaTeX Quantum Circuit diagram [closed]

I am almost done with my circuit diagram for the QAOA circuit but the \cdots does not want to cooperate. As seen there exists some wire drawn across the dots from the gate to the right and I can't ...
2 votes
1 answer
67 views

What happened to the 1/2 in the MAXCUT Problem Unitary for QAOA

I recently started to begin with QuantumComputing following the Qiskit tutorial. I worked through the basics and now reached Chapter 4.1.3 (https://qiskit.org/textbook/ch-applications/qaoa.html). I ...
0 votes
1 answer
151 views

Finding the minimum cut using QAOA

I am trying to find the minimum cut for a given graph. I am using QAOA and refering to the qiskit textbook: https://qiskit.org/textbook/ch-applications/qaoa.html. I understand I need to find the ...
1 vote
1 answer
206 views

Commutativity of XY gate

My question is a simple one: Can 2 XY gates commute ? XY gate is a 2-qubit XX+YY interaction also sometimes referred to as iSwap gate.
8 votes
1 answer
2k views

QUBO, Ising Hamiltonians and VQA

I understand that usually the combinatorial optimisation problems are turned into QUBO, which has a very simple mapping to Ising Hamiltonians. Ising Hamiltonians in turn have the desired properties of ...
1 vote
1 answer
565 views

QAOA MaxCut IBM Qiskit Example

I tried using the same example of Qiskit MAX-CUT problem for a different graph. https://qiskit.org/textbook/ch-applications/qaoa.html My graph is as follows: Using COBYLA I get a cut which is NOT a ...
1 vote
1 answer
305 views

Implementing QAOA Hamiltonian for MAX-3-SAT in Qiskit

I have read about how QAOA is used to tackle the MAX-CUT problem and wanted to test my understanding by trying to implement some code to approximate the MAX-3-SAT problem. To do so, I considered the ...
2 votes
1 answer
178 views

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 ...
1 vote
0 answers
144 views

Interpreting VQE and QAOA based solutions in portfolio optimization

I am going through portfolio optimization using Qiskit. It really looks interesting. The module has both VQE and QAOA algorithms for optimizing the portfolios. In the VQE based solution the ...
1 vote
0 answers
39 views

Error analysis on the approximation of an adiabatic evolution operator by a QAOA circuit

I would like to know what would be the approximation error of a QAOA circuit. Suppose we have time-dependent Hamiltonian $H(t) = (1 - s(t))H_{init} + s(t)H_{prob}$ where $H_{init}$ in an initial ...