What is Computational physics: Definition and 166 Discussions

Computational physics is the study and implementation of numerical analysis to solve problems in physics for which a quantitative theory already exists. Historically, computational physics was the first application of modern computers in science, and is now a subset of computational science.
It is sometimes regarded as a subdiscipline (or offshoot) of theoretical physics, but others consider it an intermediate branch between theoretical and experimental physics - an area of study which supplements both theory and experiment.

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  1. chirag1

    A Numerical evolution of Einstein-Boltzmann equations in cosmology

    I'm trying to numerically evolve the Einstein-Boltzmann equations for cold dark matter perturbations using Runge-Kutta method of the fourth order. There are 5 standard equations: $$ \begin{align} \dot{\Theta}_{r,0}+k\Theta_{r,1}&=-\dot{\Phi} \\ \dot{\Theta}_{r,1}+\frac{k}{3}\Theta_{r,0} &...
  2. P

    Fortran Errors in Fortran code for solving Laplace's equation in 3D

    hey everyone. I wrote a code in Fortran to calculate potential values or solve the Laplace equation inside a cube according to the boundary conditions mentioned in the code. this is my code: program laplace_cubic implicit none REAL*8 :: LX, LY, LZ, DELTA, MAX_ERR, ERR INTEGER :: NX, NY...
  3. jv07cs

    Programs REU Opportunities for International Students in Theoretical Physics

    I'm a physics undergrad student in Brazil and I'm about to finish my sophmore year. I'm really interested in computational and theoretical physics and I'm currently in the beginning of this year long research project with a professor in my university on the study of the 3+1 spacetime split of...
  4. benagastov

    Error while Executing "Make all" code for Quantum Espresso in Colab

    Good evening, Now I start learning Quantum Espresso and I tried to install it on Google Colab, since I already get convenient and its my habit to do all computation in Physics using google Colab. Sometimes I rent cloud gpu if I need bigger RAM and GPU when I have heavy load. You can see the...
  5. A

    Admissions PhD in CSME/Computational Physics/Biophysics from maths background

    Hello, I’m looking to apply for CSME/computational physics/biophysics PhDs in America starting in September 2024. I'm a bit scared about physics departments just because whilst I have mechanics, QM and Stat Mech I have never taken any atomic/electrodynamic classes. I would like to know if my...
  6. abdulhayee

    Admissions How to prove Physics competency to grad school admission committees?

    Greetings, This is a slightly longer post but it's coming from someone who's humbly and sincerely passionate+motivated about pursuing Physics and hence I'd be immensely grateful to everyone who can help me clear my confusions and see a ray of light and hope! You'd be doing me a solid :) My...
  7. Z

    Exploring Computational Physics: Is C++/Python Necessary?

    hello I am interested in computational physics at an amateur level is it worth while learning complex numerical methods with C++ /Python to solve partial differential equations as well as for other physical applications while a software such as mathematica can do the job for you ?
  8. gurbir_s

    A Solving this first-order differential equation for neutron abundance

    The time rate of change of neutron abundance ##X_n## is given by $$\frac{dX_n}{dt} = \lambda - (\lambda + \hat\lambda)X_n$$ where ##\lambda## is neutron production rate per proton and ##\hat\lambda## is neutron destruction rate per neutron. Given the values of ##\lambda## and ##\hat\lambda## at...
  9. P

    Physics Looking to transition from data science to computational physics

    In my late twenties, currently working as a data scientist in the UK, looking to sit A level maths, further maths and physics as a private candidate (not going through a distance learning provider) and pursue a joint degree in physics and computer science (which I know both St Andrews and...
  10. A

    Math Applied math work opportunities for high school students?

    Hi. I'm a high school student interested in applied math, including but not limited to climate modelling, auto differentiation, and simulations. It'd be really nice if I could get some experience in those fields in a structured learning environment, like an internship, with mentors if possible...
  11. user366312

    A What is meant by pruning and enrichment?

    As far as I understand: Pruning means deleting something. Enrich means to enhance/increase weight. Now my question is, in the case of the PERM algorithm, Are we deleting some polymers chains? Or, are we deleting some beads in all polymer chains? Are we increasing the weights of some...
  12. megapiano

    Need help with N-body simulation

    Many years ago, for my high school senior project, I wrote a solver for the N-body problem that is performance-optimized using the Barnes-Hut algorithm. (the optimization algorithm is not relevant to my question.) In one particular simulation, I simulated a spiral galaxy. The simulation is not...
  13. W

    Coding of Spin Spin correlation function

    I tried to code spinoperators who act like $S_x^iS_x^j$ (y and z too) and to apply them to the states, which works fine. I am not sure about how to code the expectation value in the product Space. Has anyone pseudo Code to demonstrate that?
  14. Mr_Allod

    Analysing the Normal Modes and Dynamics of a Cluster of Atoms

    I am trying to analyse the dynamics of a cluster of 79 atoms. The system can be described with: ##\omega^2 \vec x = \tilde D\vec x## Where ##\omega^2## (the eigenvalues) are the squares of the vibration frequencies for each mode of motion, ##\tilde D## is the "dynamical matrix" which is a...
  15. W

    A Define spin operators for numerical groundstate obtained by ED

    Hi, I want to measure spin components of a ground state of some models. These ground states are obtained by ED. The states for constructing the Hamiltonian are integers representing spins in binary. As the ground state (and the other eigenvectors) are now not anymore in a suitable representation...
  16. orochi

    Courses Learning Parallel Computation as a particle physicist

    I am starting my Master's Degree in Nuclear and Particle Physics, should i invest in taking a course in Parallel Computation? I know the role that Parallel Computation has in particle physics, but is there any use in a particle physicst learning about parallel computation, or could it be...
  17. C

    A How are the thermal expansion of a solid and the stress tensor related?

    My idea is this: tensor stress is directly related to the internal pressure of a solid. That is to the force that the neighboring atoms exert each other in relation to a unit of surface. When I heat a solid we can have the phenomenon of thermal expansion: this is connected to the fact that a...
  18. J

    Best Environment/Programming Language for simple physics Simulations

    Hello, I am looking for something to simulate/visualize simple particles and classical physics equations, preferably moving in real time Requirements: -Able to turn matrices/functions into geometric representations(visualize sphere, visualize a cylinder etc.) -Can do the classic ball bouncing...

    Other Unsure between computational physics and data science

    What would be better to choose as a career COMPUTATIONAL PHYSICS or DATA SCIENCE Is there any pro and con?
  20. S

    Moving from Computer Science to a PhD in Computational Astrophysics

    Hi I am planning to do phd in computational astrophysics or planetary science or scientific computing simulation (least preferred in case i am not allowed to the other two). Right now I have bachelors in computer science and planning to do masters in the same. My query is should i join...
  21. V

    Courses Undergraduate Math Course Selection Question

    Hello, I'm a college undergraduate sophomore interested in eventually getting a Ph.D. in biophysics or computational physics. I have the chance to take several graduate math classes in the next two years, and I was wondering which ones would be the most useful for me in the future. They are...
  22. Auto-Didact

    A The Wolfram Model & Wolfram Physics Project

    As seen in the video above, ten years ago Stephen Wolfram teased a computational physics program which he simply called 'Physics'; some of this work was outlined in his magnum opus "A New Kind of Science". A few days ago he has finally given a huge update of this in his blog...
  23. CrosisBH

    Computing the wave function of a square potential

    The book's procedure for the "shooting method" The point of this program is to compute a wave function and to try and home in on the ground eigenvalue energy, which i should expect pi^2 / 8 = 1.2337... This is my program (written in python) import matplotlib.pyplot as plt import numpy as...
  24. CrosisBH

    Trouble with Electric Potential Boundaries (Computational Physics)

    This is in python: #ELECTRIC POTENTIAL from mpl_toolkits.mplot3d import Axes3D from matplotlib import cm import numpy as np import matplotlib.pyplot as plt dx = 0.1 dy = 0.1 xrange=np.arange(-1,1,dx) yrange=np.arange(-1,1,dy) X,Y = np.meshgrid(xrange, yrange) max_dV = 10e-5 blockRadius = 3...
  25. CrosisBH

    [Computational Physics] Modeling the path of a Baseball with drag

    import matplotlib.pyplot as plt import numpy as np #constants and conditions initial_velocity = 49.1744 #m/s, book has 110mph velocity_angle = 35 * np.pi / 180 #coverted to radians because numpy only likes radians gravity = 9.8 #m/s^2 dt=0.1 windspeed = 4.4704 #m/s book has 10mph #calculating...
  26. patrykh18

    What Are Suitable Plasma Physics Project Ideas for an Undergraduate?

    Summary:: I am looking for topics to give a presentation on. Hi everyone. If this is in the wrong section feel free to move it. Anyway, as part of our lab course, on top of doing experiments we will also have to prepare a 20 minute presentation on a chosen topic on physics. This is not like...
  27. K

    I Numerical Solution to the Rayleigh Plesset Equation

    I have been trying to numerically solve the Rayleigh Plesset equation: $R\ddot{R} + \frac{3}{2}(\dot{R})^2=\frac{p_g-p_0-p(t)}{\rho_l}-4\mu\frac{\dot{R}}{R}-\frac{2\gamma}{\rho_lR}$ using the odeint python function. The code is given below: import numpy as np from matplotlib import pyplot as...
  28. S

    Physics Computer vision engineer looking for career change into physics

    I am a computer science graduate working in computer vision , remote sensing field for a private company. Been studying physics on my own for curiosity(A levels, H&R books, feynman essentials) . I developed interest in physics few years back and I have been searching for ways to convert my...
  29. E

    Other Computational physics bachelor project any ideas?

    I am coming closer to finishing my undergraduate studies, and thus, I need to write a bachelor project on a certain topic. There are millions of topics, and fields to choose from, and I simply don't know what to choose. I did some thinking, and research, and realized that the most feasible area...
  30. M

    A Is computational Physics a hard major?

    Is computational Physics a hard major? To what extend I should learn mathematics and Computer Science besides learning Physics?
  31. T

    Computational Physics Simulations

    I am currently learning python and c++ and interested in the near distant future on exploring some computational physics simulations. But have seem to hit a road block. I have just finished my undergrad in physics and have some time to explore physics concepts that were never really cleared up...
  32. Ramil

    Quantum Monte-Carlo calculation of Green's function

    Introducing the spacetime spherical symmetric lattice, I use the following notifications in my program. i - index enumerating the nodes along t-coordinate, j - along the r-coordinate, k - along the theta-coordinate, l - along the phi-coordinate. N_t - the number of nodes along t-coordinate. N_r...
  33. J

    Should Physics Majors Learn Object-Oriented Programming?

    Would physics majors benefit from learning how to do Object Oriented programming?
  34. L

    A What is best way to start learning DMRG for Fermions?

    I want to learn the density matrix renormalization group (DMRG) method in traditional formalism (not MPS). While there are many good introductory level articles available for bosonic (and spin) systems, I have not encountered any introductory level article which deals with fermionic systems i.e...
  35. L

    A How to numerically diagonalize a Hamiltonian in a subspace?

    I want to exactly diagonalize the following Hamiltonian for ##10## number of sites and ##5## number of spinless fermions $$H = -t\sum_i^{L-1} \big[c_i^\dagger c_{i+1} - c_i c_{i+1}^\dagger\big] + V\sum_i^{L-1} n_i n_{i+1}$$ here ##L## is total number of sites, creation (##c^\dagger##) and...
  36. K

    Perform an image deconvolution using FFTs and Python

    Homework Statement [/B] This problem is from Mark Newman's Computational Physics, problem 7.9, found at http://www-personal.umich.edu/~mejn/cp/exercises.html. The problem gives us a blurry convolved image, according to a Gaussian point spread function and our objective is to deconvolve it to...
  37. TachyonLord

    The order of calculating velocity and position alters the solution?

    So I tried solving the differential equation for a spring - mass system using Euler's Algorithm in Python. The equation being d2x/dt2= -4π2x (The equation was obtained by Dimensional Analysis) here x and t are both dimensionless equivalents of position...
  38. astroman707

    Programs Is a 2nd major in comp sci useful in computational physics?

    I'm majoring in physics and I'm planning on pursuing computational astrophysics in graduate school. Will a second major in computer science/programming look good to graduate schools, and/or will it give me great advantages in the field of computational astrophysics or astronomy?
  39. V

    Hamiltonian for a 1D-spin chain

    Homework Statement [/B] A 1D spin chain corresponds to the following figure: Suppose there are ##L## particles on the spin chain and that the ##i##th particle has spin corresponding to ##S=\frac{1}{2}(\sigma_i^x,\sigma_i^y,\sigma_i^z)##, where the ##\sigma##'s correspond to the Pauli spin...
  40. J

    Quantum I need a book to solve Schrodinger's eqn numerically

    I have found this one that looks perfect: https://www.amazon.com/dp/331999929X/?tag=pfamazon01-20 THe problem is that it has not been published yet :( , but I can't believe there is no other book on the subject. What I want is to solve numerically the Schrodinger equation with no special...
  41. G

    A How can I simulate 2D correlated data with continuous-valued variables?

    Not sure this is the right area to post this. Let's say I have particles on a lattice, and they all have some property (ie, color) that is correlated at some known correlation length. I want to simulate this! In 1D I could do something like have color be a random walk in the given dimension...
  42. Arij

    Other Why Choose Computational Physics?

    Hello, I've been wondering lately why would one change study path from theoretical or applied physics to computational physics or become a simulation expert? I am a physics graduate myself and based on the job market where I live I might need to pursue material sciences or computational...
  43. twist.1995

    A Restricted Open Shell Hartree Fock Method

    Hello, dear scientists and forum users. I have recently finished programming the restricted closed-shell and unrestricted Hartree-Fock matrix equations. They seem to work fine for small diatomic molecules. However, I cannot understand the restricted open-shell theory that was firstly published...
  44. twist.1995

    A Symmetry Considerations in Hartree-Fock-Roothaan Method

    Hello, dear Quantum Chemists or Physicists. I have been extensively researching the restricted closed-shell Hartree-Fock method, and wrote a code that is working for diatomic molecules, like H2 or He2++. I, however, have a few unresolved questions that do not allow me to proceed further in...
  45. Hamza Elkotfi

    A What resources are available for using DFT to study 1D materials in physics?

    hello dear physicists I will work in my thesis on 1D materials using DFT as a numerical method to find the properietes of these 1D materials I would be very happy if someone can help me with references (books, links, articles, vedios ...) that could help me to advance in my work Thank you
  46. B

    I How can I convert chi-square into a matrix and graph likelihood contours?

    Hello, I'm new to the world of "numerical" astronomy/cosmology and I've been studying maximum likelihood estimation for model tests. The (analytical) theory is somewhat easy to understand, but I've been struggling with the numerical aspect of the computations. Suppose you have some model with a...
  47. S

    Programs Which subfield of physics should I choose?

    Hi everyone; I have a question, and I hope you could answer it. Well, I have a bachelor degree in physics/computer science and I plan to go to a graduate physics program; however, I don’t know which subfield is good for me. I was looking for computational astrophysics, computational condensed...
  48. jedishrfu

    Applying Computational Physics to Car/Bicycle Accidents

    This article does an analysis of a angled street intersection where a lot of fatal bicycle/car collisions happen in England using knowledge of basic Physics and some programming: https://www.wired.com/story/the-physics-of-the-69-degree-intersection-that-kills-cyclists/
  49. P

    I Computational physics - Light trajectory near black hole

    Dear all, I am currently doing a project about the light trajectory near Schwarzschild black hole. I wrote down a couple of differential equation and I have created a C++ program hoping to solve the orbit of light. However, the program results turn out to be quite weird. The differential...
  50. Q

    Physics Interested in grad school in Computational Physics, help?

    Undergrad with about a year and a half of school left here! The looming spectre of the real world has come with the realization that I do not know anywhere near enough of physics and math to satisfy me. I love math, I want more than anything to understand and do work that involves computers at...