Questions tagged [algorithms]
For questions about an algorithm as it relates to physics. DO NOT ask how to implement an algorithm, questions like that belong on Stack Overflow or Computational Science. DO NOT ask about the efficiency of an algorithm, or other such questions, questions like that belong on Computational Science.
150 questions
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References for Numerical Solutions of the Feynman Path Integral
I am looking for references that discuss numerical approaches to evaluating the Feynman path integral.
Specifically, I would like references (books, papers, or reviews) that cover:
Discretization ...
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2
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Go a step further and get the both results of $f(x)$ in Deutsch algorithm
The Deutsch-Josza algorithm gives the result in one operation of the type of a $(0,1) \mapsto (0,1)$ function $f(x)$, i.e. if $f(x)$, is constant or balanced. With the parallel computing power of a ...
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Neglected Term in the energy gradient for Variational Monte-Carlo
I'm looking into variational Monte-Carlo to determine the optimal variational parameter that corresponds to the ground state of a Hamiltonian. In general I am interested in tight binding models where ...
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Checking inverse metric and Christoffel symbols for the Kerr metric against references
I am trying to cross-check the Christoffel symbols and other very laborious geometric components in several metrics. In particular the Kerr metric is notoriously complex and results in expressions ...
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Any quantum Monte-Carlo algorithm for calculating the lowest eigenenergy in each symmetry sector?
Suppose we have a hamiltonian which has the parity symmetry (e.g., the Heisenberg model with the open boundary condition). Is there any quantum Monte-Carlo algorithm which can be used to calculate the ...
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Is there a proof for critical slow-down in Monte Carlo?
It is physically understood why the standard Metropolis-Hasting algorithm slows down near the critical temperature, since it doesn’t utilize the divergence of the correlation length. However, I’m ...
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Understanding chapter 3.1 (Laplace's equation) in Introduction to electrodynamics Griffiths 4 ed [duplicate]
I really need help to understand chapter 3.1.
What is the method of relaxation?
How can I use the method of relaxation to solve Laplace's equation?
How can I use the first and second uniqueness ...
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Can I find quantum circuit drawing of BB84 protocol somewhere?
Quantum algorithms and protocols are often expressed as circuit diagrams. But I have not been able to find the circuit diagram of BB84 protocol. Has anyone seen one?
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Simplest quantum Monte-Carlo method for the Bose-Hubbard model
I want to use quantum Monte-Carlo results to benchmark an algorithm for the Bose-Hubbard model. There are so many QMC methods in the market, so which one is the simplest one? I want the ground state ...
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Numerically computing induced magnetic field from current density
Let's say we have current density $J_i$ on a discretized grid with $(N_x \times N_y \times N_z)$ points. What is the best procedure to compute the induced magnetic field $(B_i)$ from the current ...
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An example problem to solve using 100 qubits?
Suppose we have in our possession 100 pairs of electrons.
Each electron A1 - A100 is entangled with its respective twin B1 - B100. Each entangled electron pair has been set up to have opposite spins (...
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Sensor Array Position Calibration in Anisotropic Media
Problem.
I have a sensor array consisting of $n \gg 4$ receivers at unknown locations $\langle x_n, y_n, z_n\rangle$ embedded in an anisotropic medium whose index of refraction varies as a known ...
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Are there ways to find representations of matrices given an algebra?
Given an equation (or a set of equations) involving matrices, is there an algorithm to find possible representations of these matrices?
For example, we can consider a matrix $A$ such that
$A^2=\begin{...
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Reference request: Numerical techniques, Monte-Carlo (MC), Density Matrix Renormalization Group (DMRG), Dynamical Mean-Field Theory (DMFT)
I am an undergraduate student and my previous learning in physics is more on theory instead of numerics. I would be very grateful if you can point me to good introductory lecture notes/lecture videos ...
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Algorithm for solving Poisson's equation numerically
I need an algorithm to solve Poisson's equation for gravitational potential.
$$ \nabla^2\phi = 4\pi G\rho $$
where, $\phi$ is Gravitational Potential.
I am trying PDE for the first time so, I need ...
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Dynamic Programming and legendre transformation?
I read once (I can't find it anymore:( ), that the Legendre transformation from the Lagrange formalism to the Hamilton formalism can be seen as dynamic programming.
I have never seen it like this and ...
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Algorithm that checks if a subspace of states contains a product state
Suppose I have two identical qudits, the full Hilbert space is $\mathcal{H}=(\mathbb{C}^{d})^{\otimes 2}$. Say I'm given a supspace of states $\Lambda\subset \mathcal{H}$. What is the fastest ...
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Is Shor's algorithm for factoring still efficient in the presence of small phase noise
Quantum Fourier transform of $|a\rangle\in H_N$
$$|a\rangle\longrightarrow\sum_{l=0}^{N-1}e^{\frac{i2\pi a l}{N}}|l\rangle$$
where $N=2^n$ and $H_N$ is $N$-dimensional Hilbert space.
The ...
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How Do Quantum Computers Work, Like Really [closed]
I understand in plain terms superposition and entanglement, but I'm very unclear how either of these could work as a means to increase computation power.
A helpful metaphor is that of the maze. A ...
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Is there a comparison table for quantum algorithms like VQE, QPE, QAOA, and so on?
I have one question: Recently, I studied about several algorithms like VQE, QPE, QAOA and so on. I would like to make some comparison tables about those algorithms, their strengths and weaknesses. If ...
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Final Hamiltonian for Adiabatic Grover
X-Posted on Quantum-Computing Stack Exchange
In quantum computation, there is a famous algorithm to search a marked item in an unstructured database called Grover's algorithm. It achieves a quadratic ...
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Is the universe's Kolmogorov complexity growing over time?
The Kolmogorov complexity of a deterministic universe is constant.
The Kolmogorov complexity of a nondeterministic universe grows over time. It grows whenever something happens that is not ...
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Modeling curved light in media with "complex" indices of refraction
I've written an algorithm to solve the Time Difference of Arrival (TDoA) localization problem, using Bancroft's method (see). Given the coordinates of $n$ nodes in ...
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Novikov self-consistency and computability
The Wikipedia article on the Novikov self-consistency principle has a section on time loop logic, where it discusses using time travel to solve any NP problem by finding an algorithm where the only ...
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Github for Physicists
I am wondering if there is a platform to which researchers share or publish the code they used in their research. I noticed that many researchers explain their algorithm and math and present the ...