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#quantummechanics — Public Fediverse posts

Live and recent posts from across the Fediverse tagged #quantummechanics, aggregated by home.social.

  1. Physicists Find Useful Energy Hiding in Quantum “Waste Heat”

    An atom in a cavity between two mirrors (left) acts as a heat engine in a driven-dissipative quantum…
    #NewsBeep #News #Physics #AU #Australia #QuantumMechanics #QuantumPhysics #quantumtechnology #Science #Thermodynamics #UniversityofBasel
    newsbeep.com/au/885958/

  2. Meet Rachel Chen, the 18-year-old Los Angeles student who expanded a 1997 quantum-math idea to describe entire particle systems with simple diagrams; she won $100,000

    Rachel Chen, 18, won $100,000 for her inno…
    #NewsBeep #News #Physics #AU #Australia #LosAngelesstudent #quantummathematics #QuantumMechanics #quantumparticles #QuantumPhysics #RachelChen #RegeneronScienceTalentSearch2026 #Science #spinrepresentation #Temperley-Liebalgebra #Temperley-Liebdiagrams
    newsbeep.com/au/885772/

  3. Semiconductor Physics by P.S. Kireev

    This textbook originates from lectures delivered by the author to students of the Semiconductor Materials and Devices Faculty at the Moscow Institute of Steel and Alloys. It assumes prior knowledge of subjects like Crystallography and Quantum Mechanics, allowing the material to focus exclusively on semiconductor physics without revisiting crystal lattice structures or atomic bonding. Leveraging students’ understanding of quantum mechanics, the textbook employs rigorous methods to address topics such as energy band structures and charge carrier transitions, including their interactions with lattice defects, phonons, and photons. Detailed intermediate calculations and experimental data further enhance comprehension.

    While the material is presented at a high level, it remains accessible, supported by clear derivations and illustrations. Group theory methods are introduced to simplify problem-solving but are confined to an appendix, as this subject is typically not part of technical college curricula. The book deliberately avoids covering the operation of specific semiconductor devices, treating Semiconductor Physics as a distinct discipline with a focus on fundamental principles.

    Translated from the Russian by Mark Samokhvalov

    All credits to the original uploaders, this is an optimised pdf.

    You can get the book here and here

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    CONTENTS
    Preface 9

    Chapter I. Introduction. Electron Theory of Conductivity 11

    Electron Theory of Conductivity. Ohm’s Law 11
    Mean-Free Time and Free-Path Distribution Functions 16
    Electron Distribution Function. Mean Values of Physical Quantities 20
    Semiconductors. The Classification of Materials According to Their Conductivity 31
    Semiconductor Conductivity Models. The Concept of a Hole 35
    Intrinsic and Extrinsic Conductivities 39
    Chapter II. The Fundamentals of the Band Theory of Semiconductors 42
    7. The Schrödinger Equation for the Crystal 42
    8. The Adiabatic Approximation 45
    9. Single Electron Approximation 50
    10. Periodic Field of the Crystal Lattice. Translational Operator 54
    11. Quasimomentum 59
    12. The Effective Mass of the Electron 64
    13. Relation Between Velocity and Quasimomentum 70
    14. Acceleration Operator 73
    15. Brillouin Zones 80
    16. Normalising Inside a Potential Box and the Discrete Nature of Quasimomentum 85
    17. Theory of the Quasifree Electron 90
    18. Theory of the Quasibound Electron 105
    19. Effective Mass Method. Influence of External Fields on Energy Spectrum of a Crystal 119
    20. Localised States 125
    21. Elementary Theory of Impurity States 130
    22. Surface States 138
    23. Quantisation of Electron Energy in a Magnetic Field. Landau Levels 141
    24. Pauli Principle. Concept of Metal, Semiconductor, and Dielectric 146
    25. Main Features of the Hole 153
    26. Band Structure of Some Semiconductors. Calculation Methods 158
    27. Quasiparticle Concept 175

    Chapter III. Electron and Hole Statistics in Semiconductors 180
    28. Density of States 180
    29. Electron and Hole Concentrations 189
    30. Electric Neutrality Equation 197
    31. Intrinsic Semiconductor 200
    32. Extrinsic Semiconductor. Impurity of One Type 205
    33. Semiconductor Doped with Both Acceptor and Donor Impurities 215
    34. Degenerate Semiconductor 221
    35. Density of States in a Magnetic Field 225

    Chapter IV. Kinetic Phenomena in Semiconductors 234
    36. Boltzmann’s Kinetic Equation 234
    37. Relaxation Time 241
    38. Electric Current Density and Energy Flux Density 249
    39. Kinetic Coefficients 253
    40. Conductivity of Semiconductors 261
    41. Galvanomagnetic Effects 270
    42. Hall Effect in Extrinsic Conductivity Range 280
    43. Hall Effect in a Substance with Several Types of Charge Carriers 288
    44. Magnetic Field Dependence of Hall Coefficient 294
    45. Magnetoresistive Effect 302
    46. Heat Conductivity of Semiconductors 311
    47. Thermoelectric Phenomena 318
    48. Thermomagnetic Phenomena 334
    49. General Analysis of Kinetic Phenomena 338
    50. On Kinetic Phenomena in Semiconductors with Tensor Effective Masses 348
    51. Tensorsensitive Effect. Tensorsensitivity 352
    52. Piezoresistive Effect. Piezoresistance Coefficients 359

    Chapter V. The Theory of Charge Carrier Scattering 369
    53. Effective Scattering Cross Section 369
    54. Relationship Between Relaxation Time and Effective Cross Section 378
    55. Elements of Quantum Transition Theory 383
    56. Impurity Ion Scattering 390
    57. Scattering by Neutral Impurity Atoms 398
    58. Lattice Vibrations. Normal Coordinates, Phonons 401
    59. Acoustical and Optical Lattice Vibrations 409
    60. Lattice Specific Heat. Phonon Statistics 422
    61. Scattering by Thermal Lattice Vibrations. Method of Deformation Potential 432
    62. Temperature Dependence of Charge Carrier Mobility 441
    63. Dependence of Relaxation Time on External Fields. Deviations from Ohm’s Law 452

    Chapter VI. Charge Carrier Recombination 461
    64. Continuity Equation. Lifetime 461
    65. Recombination Mechanism. Linear Recombination 472
    66. Diffusion and Drift of Nonequilibrium Charge Carriers 484
    67. Surface Recombination 492

    Chapter VII. Contact Phenomena in Semiconductors 497
    68. Debye Length 497
    69. Work Function 510
    70. Contact Potential Difference. Metal-Metal Contact 515
    71. Metal-Semiconductor Contact 519
    72. Inhomogeneous Semiconductor, p-n Junction 525

    Chapter VIII. Optical and Photoelectrical Phenomena in Semiconductors 532
    73. Light-Absorption Spectrum 532
    74. Light Absorption by Free Charge Carriers 536
    75. Cyclotron Resonance 546
    76. Intrinsic Light Absorption 555
    77. Absorption of Light by the Lattice 573
    78. Light Absorption by Electrons in Localised States 579
    79. Influence of the Ambient on Absorption Spectrum 586
    80. Photoresistive Effect 590
    81. Dember Effect. Photovoltaic Effect 599
    82. Photomagnetoelectric Effect 608
    83. Faraday Effect 613
    84. Spin-Orbital Splitting of Energy Bands 623

    Appendix. Introduction to the Theory of Groups 633

    Space Transformations 633
    Group of Symmetry Transformations. Properties of Group Elements 639
    Relation Between Groups 643
    Representation of Groups 646
    The Properties of Irreducible Representations 649
    The Basis of a Representation 652
    Direct Product of Representations 655
    Point Groups 659
    Translational Groups. Brillouin Zones 665
    The Wave Vector Group 671
    Schrödinger Equation 680
    Twin Groups. Time Inversion 684
    Recommended Literature 694

     

    #physics #quantumMechanics #semiconductors #sovietLiterature
  4. Theory Of Stellar Spectra by V.V. Sobolev

    The only source of our information on stars is their radiation. From stellar spectra we judge the structure of stellar atmospheres, their chemical composition, and physical processes taking place there. Spectrograms are interpreted on the basis of the theory of stellar spectra, wherein lies its enormous value for astrophysics. Until recently astronomers could observe stellar radiation only in a very small range of frequencies making up the visible region of the spectrum. However, about 20 years ago radio astronomy came into being which permits investigating the radiation of celestial bodies in a completely different spectral region.

    Quite recently, in connection with the launching of satellites and rockets, there arose the theoretical possibility of obtaining stellar spectra in any frequency range. So far, highly useful spectrograms of stars and the sun have been obtained in the so-called rocket ultraviolet. It is obvious that this broadening of observational data will even further increase the significance of the theory of stellar spectra. At the same time it is necessary to improve and extend this theory.

    The surface layers of stars, out of which their spectra arise, represent
    strongly ionized gases, i.e., plasma. Plasma studies are also being carried out in physics laboratories, having increased in intensity of late. Methods used by physicists in studying plasmas are in many respects similar to methods used by astrophysicists in studying stellar atmospheres. Therefore, the theory of stellar spectra is of interest not only to astrophysicists but also to physicists.

    An excellent example of the broad interest in the theory of stellar spectra is the summer seminary on problems of this theory, organized by the
    Astronomical Council of the Academy of Sciences of the USSR and the Leningrad University and held in Leningrad in June 1964* About 150 young astrophysicists and physicists of the Soviet Union participated in the sessions. This book was written on the basis of the lectures given at that time.
    The first part of the book examines atomic processes associated with the
    formation of spectra, with special emphasis on calculation of the energy levels of the atom and the probability of transitions between these levels. The second part deals with the theory of radiation transfer, which forms an important aspect of the theory of stellar spectra. The next two parts discuss the most essential problems in the formation of spectra of different types of stars and nebulae. The last part, devoted to ultraviolet spectra of celestial bodies, mainly gives a review of observational data and their qualitative interpretation (since, as yet, no quantitative theory of these spectra has been established).
    The diversity of the problems of the modern theory of stellar spectra makes it impossible to present them with sufficient completeness in a single monograph.
    The authors of this book have endeavored to acquaint the reader with the most important of these problems.

     

    You can get the book here and here

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    Preface …………………………………………… iii
    PART I. PHYSICAL PROCESSES CONNECTED WITH THE FORMATION OF SPECTRA ………… 1
    Plasma Spectroscopy (S.E. Frish) …………………….. 1
    Calculations of Atomic Energy Levels (A.P. Yutsis and Ya.I. Vizbarayte) …………… 23
    Theory of Atomic Transitions (G.F. Drukarev) ……….. 35

    PART II. THEORY OF RADIATIVE TRANSFER ……………………… 64
    Certain Nonlinear Problems of the Theory of Radiative Transfer (V.A. Ambartsumyan) ……. 64
    Radiative Diffusion in Gases (V.V. Sobolev) …………. 75
    Determination of the Populations of Excited Levels in an Optically Thick Gas Layer (V.V. Ivanov) ……….. 92
    Nonstationary Radiation Field (I.N. Minin) …………. 116
    Randomized Problem of Diffuse Reflection (R.V. Ambartsumyan) ………… 135

    PART III. SPECTRA OF FIXED STARS ……………………….. 140
    Models of Stellar Atmospheres (V.V. Sobolev) ………. 140
    Continuous Spectra of Hot White Dwarfs (A.K. Kolesov) ……. 147
    Model Atmospheres of Main-Sequence Stars of Class M (V.G. Buslavskiy) …….. 152
    Determination of the Chemical Composition of Stellar Atmospheres (A.A. Boyarchuk) ……….. 160

    PART IV. SPECTRA OF NONSTATIONARY STARS AND INTERSTELLAR MATTER ………… 170
    Spectra of Nonstationary (Variable) Stars (V.G. Gorbatskiy) ……….. 170
    Analysis of the Emission Spectra of Nonstationary Stars (A.A. Boyarchuk) ………… 194
    Spectra of Interstellar Matter (S.A. Kaplan) ………… 203
    Radio Observations of Planetary Nebulae (Yu. N. Pariyskiy) ………. 216

    PART V. SPECTRA OF CELESTIAL BODIES IN THE FAR ULTRAVIOLET REGION ……….. 220
    Spectra of Celestial Bodies in the Far Ultraviolet Region (G.A. Gurzadyan) ………. 220

    #astronomy #astrophysics #physics #quantumMechanics #radiativeTransfer #sovietLiterature #stellarSpectra #stellarStructure
  5. Master Index

    A guided map across physics, biology, engineering, and AI—built around a simple idea

    Persistence is not generated, but permitted.

    Systems don’t fail because they “break.”

    They fail because their boundaries were misclassified.

    Core structure
    state → constraint → resolution → persistence

    From: - Titanic / Vasa / Challenger
    – biological regulation
    – AI hallucination & drift
    – institutional collapse

    Same pattern
    only admissible states persist

    This is the interface.
    Start anywhere. Follow the path that fits.

    #HybridMind42 #BoundaryDynamics #BoundaryArchitecture #BFPF #HQP
    #Admissibility #ConstraintResolution #StateTransition #Persistence
    #ComplexSystems #SystemsThinking #StructuralAnalysis #FailureAnalysis
    #Physics #QuantumMechanics #Relativity #Lindblad #CPTP #Decoherence
    #Biology #Physiology #Adaptation #Homeostasis
    #ArtificialIntelligence #AI #LLM #AIAlignment #AIGovernance
    #InstitutionalFailure #DecisionMaking
    #Emergence #ScientificClarity

    substack.com/@hybridmind42/not

  6. Why Even Physicists Still Don’t Understand Quantum Theory 100 Years On

    Wiktor Mazin. Credit: Wiktor Mazin, Quantum Fractal Artist Everyone has their favourite example of a trick that reliably gets a certain job done, even if they don’t really understand why. Back in the day, it might have been slapping the top of your television set when the picture went fuzzy. Today, it might be turning your computer off and on again. Quantum mechanics the most successful and important theory in modern physics is like that. It works wonderfully, explaining things from lasers […]

    onlinemarketingscoops.com/2025

  7. I've read a lot of books about black holes. Some have more impressive illustrations/visual aids than others.

    While this particular book doesn't have the most impressive visual aids, it does a marvelous job of describing the fundamental unit of information; the bit, contained within the smallest scale possible, the Planck length.

    #information #bit #QuantumMechanics #quantum #ModernPhysics #BlackHole #BlackHoleFriday #Relativity #Planck #ReadingThisWeekend #Physics

  8. Reasons behind a multiverse: inflationary cosmology, string theory, and quantum mechanics offer theoretical foundations. Fine-tuning and cosmological evidence contribute to the puzzle. The quest for truth continues!

    Stream the latest on @QuantaMagazine’s #TheJoyofWhy now on #ApplePodcasts.

    #SpaceMastodon #Spacedon #Space #AstronomyMastodon #Astrodon #Astronomy #ScienceMastodon #Sciencedon #Science #Multiverse #InflationaryCosmology #StringTheory #QuantumMechanics #Podcasts

  9. ‘Observer’ blends way-out quantum science and fiction
    Do we each create our own reality? Could different observers create measurably different realities? It's a fantastical line of thought that has sparked scientific inquiries as well --- and now the science and the fiction
    cosmiclog.com/2023/01/09/obser
    #FictionScienceClub #Books #CLUBClub #Consciousness #FictionScience #NancyKress #QuantumMechanics #RobertLanza #ScienceFiction

  10. ‘Observer’ blends way-out quantum science and fiction
    Do we each create our own reality? Could different observers create measurably different realities? It's a fantastical line of thought that has sparked scientific inquiries as well --- and now the science and the fiction
    cosmiclog.com/2023/01/09/obser
    #FictionScienceClub #Books #CLUBClub #Consciousness #FictionScience #NancyKress #QuantumMechanics #RobertLanza #ScienceFiction

  11. ‘Observer’ blends way-out quantum science and fiction
    Do we each create our own reality? Could different observers create measurably different realities? It's a fantastical line of thought that has sparked scientific inquiries as well --- and now the science and the fiction
    cosmiclog.com/2023/01/09/obser
    #FictionScienceClub #Books #CLUBClub #Consciousness #FictionScience #NancyKress #QuantumMechanics #RobertLanza #ScienceFiction

  12. ‘Observer’ blends way-out quantum science and fiction
    Do we each create our own reality? Could different observers create measurably different realities? It's a fantastical line of thought that has sparked scientific inquiries as well --- and now the science and the fiction
    cosmiclog.com/2023/01/09/obser
    #FictionScienceClub #Books #CLUBClub #Consciousness #FictionScience #NancyKress #QuantumMechanics #RobertLanza #ScienceFiction

  13. ‘Observer’ blends way-out quantum science and fiction
    Do we each create our own reality? Could different observers create measurably different realities? It's a fantastical line of thought that has sparked scientific inquiries as well --- and now the science and the fiction
    cosmiclog.com/2023/01/09/obser
    #FictionScienceClub #Books #CLUBClub #Consciousness #FictionScience #NancyKress #QuantumMechanics #RobertLanza #ScienceFiction

  14. Seeqc raises $5M to help make quantum computing commercially viable - Seeqc, a startup that is part of a relatively new class of quantum computing companies that is looki... more: feedproxy.google.com/~r/Techcr #emerging-technologies #integratedcircuits #quantummechanics #blueyardcapital #venturecapital #recentfunding #d-wavesystems #systemonachip #newyorkcity #mventures #startups #newyork #energy #newlab #merck #qubit #seeqc #tc