EJTP 9, No. 26 (2012) 135–146 Electronic Journal of Theoretical Physics
The Fine Structure Constant and Interpretations of Quantum Mechanics
Ke Xiao∗ P.O. Box 961, Manhattan Beach, CA 90267, USA
Received 10 October 2011, Accepted 7 December 2011, Published 17 January 2012
Abstract: The fine structure constant give a simple derivation of the localized wavefunction, Schrödinger equation, double-slit and the uncertainty principle in Quantum Mechanics. The wave-particle duality link to the space-time property of matter by Planck constant. The 2 2 double-slit formula is |ψX | =2|sinc(a kX)| [1 + cos(akX − ωδT + ϕ)], where the cross-linked T = T cos (θ ) angle for double-slit, 1 c 2 and vice versa. c Electronic Journal of Theoretical Physics. All rights reserved.
Keywords: Fine structure constant; Wavefunction; Uncertainty Principle; Quantum Mechanics PACS (2010): 03.65.-w; 42.25.Fx; 61.05.fg
1. Introduction
The fine-structure constant α is deeply involved in the Quantum theory.[1,2] Pauli consid- ered quantum mechanics to be inconclusive without understanding of the fine structure constant.[2] Feynman also said that nobody understands quantum mechanics.[3] There are many controversies surrounding its reality, determinative, causality, localization and com- pleteness. Beyond the Copenhagen interpretation, other interpretations include Many- World, Hidden Variable, de Broglie-Bohm, Ensemble, von Neumann/Wigner, Quantum logic, etc, each with its own compromises. As a new approach, here we discuss a fine structure constant interpretation of Quantum Mechanics.[4] (1) Wavefunction and Wave-Particle Duality One basic problem in the quantum interpretation is the wavefunction. From 1926 to Hˆ Ψ=i ∂ Ψ 1928, there were some proposed quantum wave equations ∂t ; for example
∗ Email: [email protected] 136 Electronic Journal of Theoretical Physics 9, No. 26 (2012) 135–146
[ −2 ∇2 − (r)]Ψ(r )= ∂ Ψ(r )( ) ¨ 2μ V ,t i ∂t ,t a Schrodinger (1) → 1 (→ · (→ − ))2 + ]Ψ = ∂ Ψ ( ) 2m σ p qA qφ 1,2 i ∂t 1,2 b Pauli 2 mc 2 1 ∂ [∇ − ( ) ]Ψ(r )= Ψ(r )() − ,t c2 ∂t ,t c Klein Gordon 2 3 ∂ [βmc + αkPkc]Ψ1,2,3,4 = i Ψ1,2,3,4 (d) Dirac k=1 ∂t where the non-relativistic equations are (a) for the atomic electron configuration and (b) for the Dirac limitation of spin-1/2 particles, and the other two relativistic quantum equations are (c) for the spin-0 free particle and (d) for the spin-1/2 particle-antiparticles. The different Hamiltonians Hˆ on the left-side were proposed based on the imitations of various classical physical processes, such as Schrodinger’s Hamiltonian imitating the optical wave equation. The eigenvalues of a negatively charged electron orbiting the positively charged nu- cleus are determined by the time-independent Schrödinger equation Hˆ Ψ(r)=EΨ(r).[5]
Wavefunction Ψnlm =Rnl (r)Ylm (θ, φ) (n, l, m are quantum numbers) is geometri- cally quantized in a 3D cavity. According to Born, Ψ is the probability amplitude and ΨΨ∗ is the probability density.[6] Each state only allows two counter-spin electrons (m = ± 1 ) e2 |Ψ |2 = |Ψ |2 s 2 per the Pauli principle, nlm α c nlm is the probability density of the paired charge. The Schrödinger wavefunction Ψnlm indeed describes the twins in a box. Dirac’s√ relativistic quantum equation solves the spin-1/2 problem. Then, e |Ψ |2 = |Ψ |2 nlmms α c nlmms is the probability density of the charge. The fine structure constant can be defined as the conservation of angular momentum
e2 = ±α (2) c The wavefunction had an entropy format S = klnΨ for Hˆ Ψ=EΨ in Schrödinger’s first paper in 1926.[5] The Boltzmann constant k is linked to α by the dimensionless black- 2 = e2( 4σ )1/3 =( p )1/3 =086976680 = body radiation constant αR and primes αR ck4 p2+1 α . α 1 Ψ(r ) |Ψ(r )|2 157.555 .[7] A plane wave function ,t and the Born probability density ,t are
− i p·r−Et − i Ψ(r,t)=Ae ( ) = Ae Etψ(r)=f(t)ψ(r) (3) ∗ − i − i ∗ |Ψ(r,t)|2 =ΨΨ =[Ae Etψ(r)][Ae Etψ(r)] − i i ∗ = Ae Etψ(r) · Ae Etψ (r)=A2|ψ(r)|2 The Einstein/de Broglie wave-particle duality is linked to the reciprocal space- time properties of matter.[8,9] Note that period T =1/ν [T] and wavelength λ = 1/k [L], the property of particle-wave is defined by the spin over time-space. E = ω i.e.E= hν = h/T (spin/time) (4) p = k i.e. p = hk = h/λ (spin/space) where the conservation of angular momentum in the reduced Planck (Dirac) constant h = ET = pλ (i.e., = E/ω = p/k), and the electron spin /2 can only be interpreted by the 4-dimensional spacetime of the relativistic Dirac equation.[10,11] Electronic Journal of Theoretical Physics 9, No. 26 (2012) 135–146 137
(2) Schrödinger Equation Derivation From α We notice that e2/c in (2) has the same dimension with , Et,andp · r. Let’s use i = −1/i,ande−iπ = −1=i2 =lne−1 to rewrite (2) in the four-dimensional space-time {r,t} = {x, y, z, t}, i.e., link the charge to space, time, and spin
e2 = p · r − Et = ±α = ±i2 · α · lne−1 = i ln e∓iα (5) c where (p · r − Et)/ =(k · r−ωt)=k(r−ct) link to the relativity. (5) may also work for Et or p · r separately (e.g., let t ≡ 0 for the time-independent wavefunction). From (5),
´ ln ∓iα = − i (p · r−Et)=− (k · r− t)= Ψ du =lnΨ e i ω A u A (6)
i iHˆ t/ iEt/ − In Hilbert space (e = e ), a nonlocal plane wavefunction Ψ(r,t)=Ae Etψ(r), i.e., Ψ(r,t)=Ae−i(p·r−Et)/ is defined as the exponential (6), and the wavefunction can be locally quantized by the fine structure constant as (5)
− i p·r−Et Ψ(r,t)=Ae ( ) = Ae∓iα = A cos(∓α) ∓ iA sin(∓α)=a ∓ bi (7) ´ Ψ(r )= (r)= −iEt/ (r) |Ψ|2 =1 In (7), obviously, ,t anψn ane ψn and V dV .Itisa Hermitian function, where the real part is an even function and the imaginary part is an − i p·r−Et − i · · · −Et odd function. From Ψ(r,t)=Ae ( ) = Ae (Px x+Py y+Pz z ),
∂ Ψ(r )=− i Ψ(r ) ∂t ,t E ,t (8) ∂2 Ψ( )=− 1 2Ψ( ) ∂x 2 x, t 2 Px x, t i.e., the operators can also be derived mathematically from (8)
Eˆ = ∂ ; Pˆ = ∇; Pˆ2 = −2∇2 i ∂t i (9)
The Hamiltonian Hˆ = Tˆ + Vˆ = E is the sum of kinetic and potential energy, and T = 1 P2 2μ . In this way, the Schrödinger equation can be derived from the fine structure constant (2)
[ −2 ∇2 − (r)]Ψ(r )= ∂ Ψ(r ) 2μ V ,t i ∂t ,t (10) −2 ∇2 − (r)]Ψ(r)= Ψ(r) 2μ V E
To solve the Schrödinger equation for the atomic electron configuration, we need to convert Ψ(r)=Ψ(x, y, z) to Ψ(r)=Ψ(r, θ, φ). However, the quantum principle is inde- pendent of the coordinate system. The Schrödinger equation can also be mathematically transformed into Heisenberg matrix mechanics or Feynman path integral formulation. Therefore, the quantum principle is also independent of the mathematical expression (some confusion may be caused by usage of different symbols and terms). Although there are different ways to describe Quantum theory, all theoretical physicists agree that 138 Electronic Journal of Theoretical Physics 9, No. 26 (2012) 135–146
the fine structure constant is the magic number , and it can not be derived from the − i p·r − Quantum Mechanics.[1,2] From (7), Ψ(r)=e ( ) = e iα is for a negatively charged electron orbiting a positively charged nucleus, which has the complex number conjugates Ψ(r)=a − bi and Ψ∗(r)=a + bi,thenΨΨ∗ is a real number for the probability density
|Ψ|2 =ΨΨ∗ =(a − bi)(a + bi)=a2 + b2 =1 (11) √ Specifically, if Ψ=a(1 − i), then the normalization from (11) yields a =1/ 2. After localization, the variable wavefunctions become complex numbers (vectors in
Hilbert space). The complex addition (vector sum) Ψ12 of Ψ1 = a + bi and Ψ2 = c + di is
Ψ12 =Ψ1 +Ψ2 =(a + bi)+(c + di)=(a + c)+(b + d)i (12)
A superposition f(x1 + x2 + ···)=f(x1)+f(x2)+··· is interpreted as a vector sum as (12). There is an interference term when calculating the probability density from (12) Ψ Ψ∗ =[( + )+( + ) ][( + ) − ( + ) ] 12 12 a c b d i a c b d i (13) =(a + c)2 +(b + d)2 = a2 + b2 + c2 + d2 +2(ac + bd)
Ψ (r )Ψ∗ (r )= 2 + 2 + 2 + 2 +2( + ) iEδt/ or 12 ,t 12 ,t a b c d ac bd e . This enlightens the physical interpretation of wavefunction. There is a hidden fine-structure constant α in the = − ( α )2 localized wavefunction (7). It naturally yields the eigenvalues En Ee n from the = 1 2 = ± ( α )4[ 3 − n ] Schrödinger equation, where Ee 2 mec ; the fine-structures EF Ee n 4 j+1/2 are from Dirac’s relativistic equation, where j = l+ms is the total angular momentum.[4] α5 1 In the magnetic field, QED yields the Lamb shift E = E 3 [k(n, l)± ] and L e 2n π(j+1/2)(l+1/2) = ± gp α4 F (F +1)−j(j+1)−I(I+1) the hyperfine structures due to the “nuclear spin” EH Ee β n3 j(j+1)(2l+1) , where the total angular momentum F is equal to the total nuclear spin I plus the total
orbital angular momentum J; the proton g-factor gp =5.585. This gives experimental confirmation of a connection between α ∼= 1/137 and β ∼= 1836 . In fact, the reduced · μ = me mp = β·me ≈ m β masses me+mp β+1 e always involve in the Schrödinger equation (10). Quantum theory not only describes the electron configurations around the nucleus, but also considers the effect of nuclear mass. Neglecting interaction between electrons, the = 1 2 =025536[MeV] n above eigenvalues are linked to Eμ 2 μc . and α .
α 2 −5 =− ( )2 ∝ =53×10 En Eμ n α . (14) α 3 n 4 −9 =± ( )4[ − ] ∝ =28×10 EF Eμ n 4 j+1/2 α . α5 1 5 −11 = [k(n,l)± ] ∝ =21 × 10 EL Eμ 2n3 π(j+1/2)(l+1/2) α . gp α4 F (F +1)−j(j+1)−I(I+1) 4 −12 =± ∝ =15×10 EH Eμ β n3 j(j+1)(2l+1) α /β .
2 4 5 4 −1 In (14), we have En > EF > EL > EH since α >α >α >αβ . The interpretation of entropy S = klnΨ in the statistical mechanics is the measure of uncertainty,ormixedupness to paraphrase Gibbs.[12] The wave-function Ψ is the number of micro-states as the statistical information or probability amplitude. Electronic Journal of Theoretical Physics 9, No. 26 (2012) 135–146 139
(3) Double-slit Interference Derivation with α The interference of Young’s double-slit experiments is the “central paradox” of Quan- tum Mechanics.[3] The quanta exhibit strange behavior after passing through the double- slits: (a) There is a definite cosine-type symmetric interference pattern for the multi- quanta (photon or electron), regardless of whether they all come together or one at a time; (b) The individual quanta has an unpredictable path and target point; (c) There is a white background noise, a photon can be found even in the forbidden-zone; and (d) No interference for single-slit. In Fig. 1 (right), the 2D double-slit plane is illustrated so that the slits 1 and 2 are at x and −x, a moving target receiver at the point X, with distance 2 2 1/2 2 2 1/2 Y between the double-slit and target, L1 =[Y +(X +x) ] and L2 =[Y +(X −x) ] . Note that the experimental condition requests Y X |x| λ,soL ∼= aX is linear.
Figure 1 The cross-linked photon scattering (left) and 2D illustration of Double-slit (right)
Since the phase velocity c = νλ = ωň = ω/k and T = ω−1, from Compton scattering c c c ň − ň = ň (1 − cos θ) − = (1 − cos θ) T − T = T (1 − cos θ) c (i.e., ω ω ωc ), we have c . [13] For the each slit in Fig. 1 (left)