Hubbard Definition and 34 Threads

Lafayette Ronald Hubbard (March 13, 1911 – January 24, 1986) was an American author of science fiction and fantasy stories who founded the Church of Scientology. In 1950, Hubbard authored Dianetics: The Modern Science of Mental Health and established a series of organizations to promote Dianetics. In 1952, Hubbard lost the rights to Dianetics in bankruptcy proceedings, and he subsequently founded Scientology. Thereafter Hubbard oversaw the growth of the Church of Scientology into a worldwide organization.
Born in Tilden, Nebraska, in 1911, Hubbard spent much of his childhood in Helena, Montana. After his father was posted to the U.S. naval base on Guam, Hubbard traveled to Asia and the South Pacific in the late 1920s. In 1930, Hubbard enrolled at George Washington University to study civil engineering but dropped out in his second year. He began his career as a prolific writer of pulp fiction stories and married Margaret "Polly" Grubb, who shared his interest in aviation.
Hubbard was an officer in the Navy during World War II, where he briefly commanded two ships but was removed from command both times. The last few months of his active service were spent in a hospital, being treated for a variety of complaints.
Scientology became increasingly controversial during the 1960s and came under intense media, government and legal pressure in a number of countries. During the late 1960s and early 1970s, Hubbard spent much of his time at sea on his personal fleet of ships as "Commodore" of the Sea Organization, an elite quasi-paramilitary group of Scientologists.
Hubbard returned to the United States in 1975 and went into seclusion in the California desert after an unsuccessful attempt to take over the town of Clearwater, Florida. In 1978, Hubbard was convicted of fraud after he was tried in absentia by France. In the same year, eleven high-ranking members of Scientology were indicted on 28 charges for their role in the Church's Snow White Program, a systematic program of espionage against the United States government. One of the indicted was Hubbard's wife Mary Sue Hubbard, who was in charge of the program; L. Ron Hubbard was named an unindicted co-conspirator.
Hubbard spent the remaining years of his life in seclusion in a luxury motorhome on a ranch in California, attended to by a small group of Scientology officials. He died at age 74 in January 1986. Following Hubbard's death, Scientology leaders announced that his body had become an impediment to his work and that he had decided to "drop his body" to continue his research on another plane of existence. Though many of Hubbard's autobiographical statements have been found to be fictitious, the Church of Scientology describes Hubbard in hagiographic terms and rejects any suggestion that its account of Hubbard's life is not historical fact.

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  1. P

    A Hard-Core Boson Model in K space

    Hello, I am interested in the following model: $$ H = \sum_{<i,j>} -t (c_i c_j^{\dagger} + \text{H.C.}) + U (n_i n_j) + \sum_{<<i,j>>} -t' (c_i c_j^{\dagger} + \text{H.C.}) + U' (n_i n_j) $$ where \( <i,j> \) indicates nearest neighbors, and \( <<i,j>> \) indicates next-nearest neighbors...
  2. dieon

    I Gap Equations Plotting Error in Python: Need Help Debugging

    I’ve been working on solving gap equations related to superconductivity using Python, in the context of RMFT using the t-J model of the Hubbard Hamiltonian. My goal is to calculate and plot the variables (\Delta_x), (\Delta_y), (\xi_x), and (\xi_y) against the doping concentration (x). However...
  3. H

    A Deriving the perturbative expansion from Hubbard to Heisenberg

    In the youtube lecture “electron interaction and the Hubbard model” at the time 2:23:00, we have the following self-consistent equation with energy appearing at both sides: $$(\hat P \hat H_0 \hat P+\hat P \hat H_1 \hat Q (E-\hat Q \hat H_0 \hat Q)^{-1} \hat Q \hat H_1 \hat P) |\phi...
  4. G

    L. Ron Hubbard - the art, not the man

    L. Ron Hubbard was a con man, abuser, liar, cheat, megalomaniac, pathetic excuse for a human being. Everyone, myself included, knows that. But that was the man. When it comes to his art, I'll bet at least 1% of his work can be called decent, to say the least. What do you guys say? Yay or nay?
  5. S

    A Graphene's Hubbard U and nanotube's U

    PhysRevLett.106,236805 (2011) seems to state that Graphene has U=9.3eV and PRB 55-R11973 (1997) states that nanotube has U=u/N. However, it's not unusual for them to be hubbard U systems
  6. schwarzg

    A Simultanious eigenstate of Hubbard Hamiltonian and Spin operator in tw

    Please see this page and give me an advice. https://physics.stackexchange.com/questions/499269/simultanious-eigenstate-of-hubbard-hamiltonian-and-spin-operator-in-two-site-mod Known fact 1. If two operators ##A## and ##B## commute, ##[A,B]=0##, they have simultaneous eigenstates. That means...
  7. A

    A Manipulations with Hubbard operators

    Hi, I'm starting to study how to use Hubbard operators and I cannot understand one property: Consider the hopping terms for a lattice Hamiltonian with bosons: $$\sum_{i,j\neq i} t_{i,j} b^\dagger_i b_j$$ when writing this term in the basis of Hubbard operators $$X^{a,b}_i =| a,i \rangle \langle...
  8. Math Amateur

    MHB The Derivative in Several Variables .... Hubbard and Hubbard, Section 1.7 ....

    I am reading the book: "Vector Calculus, Linear Algebra and Differential Forms" (Fourth Edition) by John H Hubbard and Barbara Burke Hubbard. I am currently focused on Section 1.7: Derivatives in Several Variables as Linear Transformations ... I need some help in order to understand some...
  9. G

    A Diagonalization of Hubbard Hamiltonian

    Hi guys! I am starting to study Hubbard model with application in DFT and I have some doubts how to solve the Hubbard Hamiltonian. I have the DFT modeled to Hubbard, where the homogeneous Hamiltonian is $$ H = -t\sum_{\langle i,j \rangle}\sigma (\hat{c}_{i\sigma}^{\dagger}\hat{c}_{j\sigma} +...
  10. Math Amateur

    MHB Why Can't Two Functions Cover the Unit Circle?

    I am reading the book: "Vector Calculus, Linear Algebra and Differential Forms" (Fourth Edition) by John H Hubbard and Barbara Burke Hubbard. I am currently focused on Section 3.1: Manifolds ... I need some help in order to understand Example 3.1.3 ... ... Example 3.1.3 reads as follows:In...
  11. Math Amateur

    MHB Geometric Interpretation of k-Forms from H&H's Vector Calculus

    I am reading the book: "Vector Calculus, Linear Algebra and Differential Forms" (Fourth Edition) by John H Hubbard and Barbara Burke Hubbard. I am currently focused on Chapter 6: Forms and Vector Calculus ... I need some help in order to understand some notes by H&H following Figure 6.1.6 ...
  12. S

    Solution of Bose Hubbard model using ARPACK

    Sir currently I am trying to solve a system which has 8 sites and each site can have 3 possible states(0 or 1 or 2).So the dimension of matrix is 6561*6561.The lapack works good till 3000*3000.But for larger system it fails.I have studied the dsdrv1.f example from arpack where they have solved...
  13. L

    A Hubbard model diagonalization in 1D K-space for spinless Fermions

    I am trying to diagonalize hubbard model in real and K-space for spinless fermions. Hubbard model in real space is given as: H=-t\sum_{<i,j>}(c_i^\dagger c_j+h.c.)+U\sum (n_i n_j) I solved this Hamiltonian using MATLAB. It was quite simple. t and U are hopping and interaction potentials. c...
  14. A

    A Difference between Hubbard and Heisenberg-model

    Hi, I read a chapter about the Heisenberg-model, and then something about the Hubbard-Model. The Heisenberg-model just shows, that neighbouring spins allign antiparallel if J<0. The Hubbard-Model says, that there is a hopping probability t and an Coulomb replsion, so that a material becomes...
  15. D

    Evaluating partition function (stuck for weeks)

    Hi, I'm trying to calculate the partition function for a certain system and I arrived at an expression for the partition function $Z$, and have been stuck here for two weeks at the least. This is not a homework problem. If this is the wrong place to post a question like this, could you please...
  16. R

    Calculus Hubbard and Hubbard for multivariate calculus

    I've taken the single and multivariate calculus classes at my school, (college class offered in my high school for accelerated students). I'm currently a junior, but in the summer of my senior year, I plan to read a book on proofs, brush up on math glossed over by the american education system...
  17. S

    A Treatment of singlets in the Hubbard model

    I'm using the general Hubbard model (H = U \sum n_{i,\uparrow} n_{i,\downarrow} - t \sum (c^{\dagger}_{i,\sigma} c_{i+1,\sigma} + c^{\dagger}_{i+1,\sigma} c_{i,\sigma})) to solve for eigenstates of simple quantum dot configurations. For the case of a double dot with two electrons in singlet...
  18. R

    Calculus Take Math Further: Hubbard and Hubbard at UCSD

    I am currently in 11th grade and will, by the end of the year, complete calculus I II and III, as well as linear algebra. The rigor of these programs at my school is, from my point of view, hardly satisfying, though I haven't had issues with it yet. (we use the stewart book, and anton for linear...
  19. T

    Calculus Vector Calculus Hubbard enough for Physics?

    Hello everyone, How far can the book take me before I have to read another book on the subject? Thanks :)
  20. Thor90

    Eigenstate solution for a spin chain with Hubbard model

    Homework Statement I am trying to solve the model analitically just for 2 sites to have a comparison between computational results. The problem is my professor keeps saying that the result should be a singlet ground state and a triplet of excited states, but when I compute it explicitally I...
  21. A

    Hubbard Stratonovich/Gaussian Function Integration

    I need some help on this since I clearly am not confident with Gaussian functional integration. Can anyone explain where the marked identities on the picture hold? I assume you have to use some formulas for Gaussian functional integration, but the only thing I could find is the one given in the...
  22. A

    Hubbard Stratonovich transformation

    Introducing the Hubbard Stratonovich transformation my book uses an expression for completeness that I don't understand (the one indicated on the picture). Can anyone explain why this is indeed unity?
  23. U

    Calculus Multivariable Calculus, Hubbard and Hubbard and Lang's

    I do not know multivariable calculus. I have studied out of Apostol Vol.1. I do not want to learn the material from Apostol Vol. II. Therefore I want to know If it would be worthwhile to go through Hubbard and Hubbard's 'Vector Calculus, Linear Algebra, and Differential Forms' after going...
  24. L

    Difference between Hubbard and tJ model

    What is the difference between Hubbard and tJ model? Does anyone knows?
  25. P

    Why Does the Hopping Term in the Hubbard Model Project to Zero at Half-Filling?

    This is a question from Altland and Simons book "Condensed Matter Field Theory". In the second exercise on page 64, the book claims that if we define \hat P_s, \hat P_d to be the operators that project onto the singly and doubly occupied subspaces respectively, then at half-filling the...
  26. Q

    Negative kinetic energy in Bose Hubbard mode?

    Too familiar with Bose Hubbard model, but suddenly got stuck by a simple question: Why is the kinetic term (to be precise should be single body part) negative?
  27. micromass

    Calculus Vector Calculus, Linear Algebra, and Differential Forms by Hubbard

    Author: John Hubbard, Barbara Hubbard Title: Vector Calculus, Linear Algebra, and Differential Forms: A Unified Approach Amazon Link: https://www.amazon.com/dp/0971576653/?tag=pfamazon01-20
  28. S

    Two-site Hubbard model eigenstate-problem

    Homework Statement L.S., I'm breaking my head over this problem! To anyone who can help me out: thanks a lot! Consider a two-point grid (point a en point b) and two electrons occupying those points, (they can both occupy one point at the same time), both wit spin-up or spin-down. Now, they...
  29. maverick_starstrider

    COMPLETE Derivation of Heisenberg and Hubbard Models?

    Does anyone know of a COMPLETE derivation of the Hubbard Model and then the Heisenberg model from it. What I mean by complete is pedagogical including all (or at least most) steps. Books like Assa Auerbach's and Altland and Simons are worthless for these kind of things (in fact IMHO those...
  30. maverick280857

    Canonical Transformation of the Hubbard Model

    Hi, Suppose we have a 2 site Hubbard model, with the hopping Hamiltonian given by H_t and the Coulomb interaction Hamiltonian given by \hat{H}_U. In the strong coupling limit (U/t >> 1), we define a canonical transformation of \hat{H} = \hat{H}_U + \hat{H}_t, as H' =...
  31. D

    Hubbard model of graphene in high U limit

    After considering the thread https://www.physicsforums.com/showthread.php?t=474384 I began to think about the bonding in graphene. As long as we can neglect electron electron interaction, the ground state can be obtained almost trivially in a tight binding approximation. On the other hand...
  32. B

    Comp. GS of hubbard hamiltonian

    Hi, I'm trying to repeat the numerical calculation of D Jaksch's article PRL 81,3108. It is about using variational method for the ground state of bose hubbard hamiltonian: H=-J\sum{a+i+1ai}+U\sum{nini},where i denotes the lattice index the trial function is based on Gutzwiller ansatz...
  33. A

    Ground state properties of Hubbard model

    Hello everyone, I want to know the presently existing works on the topic of ground state properties of Hubbard model (spin-1/2-, or extended- ). I am nonexpert and have not googled for useful information. Please tell me some articles or monographs on this if you know. Thanks!
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