Talasna funkcija — разлика између измена

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Верзија на датум 26. јун 2019. у 03:55

Poređenje pojmova klasičnog i kvantno harmonijskog oscilatora za pojedinačne bezspinske čestice. Ova dva procesa se veoma razlikuju. Klasični proces (A–B) predstavljen je kao kretanje čestice duž putanje. Kvantni proces (C–H) nema takvu putanju. Umesto toga, ona je predstavljena kao talas; ovde, vertikalna osa prikazuje realni deo (plavo) i imaginarni deo (crveno) talasne funkcije. Paneli (C–F) prikazuju četiri različita rešenja stojećeg talasa Šredingerove jednačine. Paneli (G–H) dalje prikazuju dve različite talasne funkcije koje su rešenja Šredingerove jednačine, ali nisu stojeći talasi.

Talasna funkcija u kvantnoj fizici je matematički opis kvantnog stanja izolovanog kvantnog sistema. Talasna funkcija je kompleksna amplituda verovatnoće, i iz nje se mogu izvesti verovatnoće za moguće rezultate merenja u sistemu. Najčešći simboli za talasnu funkciju su grčka slova ψ ili Ψ (malo i veliko psi, respektivno). Talasna funkcija je funkcija čiji stepeni slobode korespondiraju nekom maksimalnom skupu komutacionih opservacija. Kada se jednom odabere takva reprezentacija, talasna funkcija može biti izvedena iz kvantnog stanja.

Za dati sistem, the choice of which commuting degrees of freedom to use is not unique, and correspondingly the domain of the wave function is also not unique. For instance, it may be taken to be a function of all the position coordinates of the particles over position space, or the momenta of all the particles over momentum space; the two are related by a Fourier transform. Some particles, like electrons and photons, have nonzero spin, and the wave function for such particles includes spin as an intrinsic, discrete degree of freedom; other discrete variables can also be included, such as isospin. When a system has internal degrees of freedom, the wave function at each point in the continuous degrees of freedom (e.g., a point in space) assigns a complex number for each possible value of the discrete degrees of freedom (e.g., z-component of spin) – these values are often displayed in a column matrix (e.g., a 2 × 1 column vector for a non-relativistic electron with spin 12).

Prema superposition principle of quantum mechanics, wave functions can be added together and multiplied by complex numbers to form new wave functions and form a Hilbert space. The inner product between two wave functions is a measure of the overlap between the corresponding physical states, and is used in the foundational probabilistic interpretation of quantum mechanics, the Born rule, relating transition probabilities to inner products. The Schrödinger equation determines how wave functions evolve over time, and a wave function behaves qualitatively like other waves, such as water waves or waves on a string, because the Schrödinger equation is mathematically a type of wave equation. This explains the name "wave function", and gives rise to wave–particle duality. However, the wave function in quantum mechanics describes a kind of physical phenomenon, still open to different interpretations, which fundamentally differs from that of classic mechanical waves.[1][2][3][4][5][6][7]

U Borovoj statističkoj interpretaciji u nerelativističkoj kvantnoj mehanici,[8][9][10] the squared modulus of the wave function, |ψ|2, is a real number interpreted as the probability density of measuring a particle's being detected at a given place – or having a given momentum – at a given time, and possibly having definite values for discrete degrees of freedom. The integral of this quantity, over all the system's degrees of freedom, must be 1 in accordance with the probability interpretation. This general requirement that a wave function must satisfy is called the normalization condition. Since the wave function is complex valued, only its relative phase and relative magnitude can be measured—its value does not, in isolation, tell anything about the magnitudes or directions of measurable observables; one has to apply quantum operators, whose eigenvalues correspond to sets of possible results of measurements, to the wave function ψ and calculate the statistical distributions for measurable quantities.

Reference

  1. ^ Born 1927, стр. 354–357
  2. ^ Heisenberg 1958, стр. 143
  3. ^ Heisenberg, W. (1927/1985/2009). Heisenberg is translated by Camilleri 2009, стр. 71, (from Bohr 1985, стр. 142).
  4. ^ Murdoch 1987, стр. 43
  5. ^ de Broglie 1960, стр. 48
  6. ^ Landau & Lifshitz, стр. 6
  7. ^ Newton 2002, стр. 19–21
  8. ^ Born 1926a, translated in Wheeler & Zurek 1983 at pages 52–55.
  9. ^ Born 1926b, translated in Ludwig 1968, стр. 206–225. Also here.
  10. ^ Born, M. (1954).

Literatura

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