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Uniform magnetic fields, flux topology and Pauli coupling
1 · Prerequisites
- Absolute and Conditional Convergence; Rearrangement; Products
- Absolute Continuity and the Sharp Fundamental Theorem of Calculus
- Analytic Semigroups and Linear Evolution Equations
- Analyticity of Holomorphic Functions; Liouville and Morera
- Approximation and Compactness in C(K)
- Arc Length and Rectifiable Curves
- Areas of Elementary Plane Figures
- Banach Alaoglu Goldstine and Krein Milman
- Banach Algebras Spectrum and Holomorphic Functional Calculus
- Banach Valued Integration and the Radon Nikodym Property
- Binary Operations, Monoids, Groups and Subgroups
- Bounded Linear Operators and Quotient Spaces
- Bounded Variation and the Riemann–Stieltjes Integral
- Cardinal Arithmetic, Cofinality and the Alephs
- Compact Operators and Riesz Schauder Theory
- Compactness
- Compactness in Metric Spaces
- Completeness, Completion, and Uniform Continuity
- Complex Coordinate and Path Transport
- Complex Differentiability and the Cauchy–Riemann Equations
- Complex Lp Spaces and Test-Function Conventions
- Complex Norms and Realification
- Complex Power Series and Analytic Functions
- Complex Subspace Realification
- Complexification, Realification and Real Structures
- Connectedness
- Construction of the Natural Numbers
- Construction of the Real Numbers via Cauchy Sequences
- Construction of the Real Numbers via Dedekind Cuts
- Continuity, IVT, EVT, and Uniform Continuity
- Continuous Functional Calculus for Self Adjoint and Normal Operators
- Contour Integration
- Convergence: Nets and Filters
- Cosets, Index and Lagrange's Theorem
- Countability and Uncountability
- Countability Axioms and Cardinal Functions
- Darboux, L'Hôpital, and Taylor's Theorem
- Density Separability and Convolution in Lᵖ
- Determinants of Matrices over a Commutative Ring
- Differentiation of Monotone Functions and the Vitali Covering Theorem
- Distributions Test Functions and Differentiation
- Divisibility, Euclidean Domains, Principal Ideal Domains and Unique Factorisation
- Dual Spaces Adjoint Operators and Annihilators
- Dual Spaces, Bilinear and Quadratic Forms, and Sylvester's Law of Inertia
- Filters and Ultrafilters
- Finite Counting, Factorials and Binomial Coefficients
- Finite Probability and the Probabilistic Method
- Foundations of the Real Numbers for Analysis
- Fourier Transform Convolution and Approximate Identities
- Fredholm Elliptic Problems and the Elliptic Spectrum
- Free Modules, Exact Sequences, Projective and Injective Modules
- Fubini and Change of Variables
- Function Space Topologies and the Exponential Law
- Fundamental Trigonometric Identities
- Gaussian Elimination, Elementary Matrices and Reduced Row Echelon Form
- Gelfand Theory and Commutative C Star Algebras
- Goursat's Theorem and Cauchy's Theorem in a Convex Domain
- Group Actions, Orbits, Stabilisers and Cayley's Theorem
- Harmonic Functions and Mean Values in Rn
- Hausdorff via the Diagonal
- Hereditary and Productive Behaviour of the Separation Axioms
- Hilbert Space Geometry and Riesz Representation
- Ideals, Quotient Rings and the Isomorphism Theorems for Rings
- Improper and Parameter-Dependent Multiple Integrals
- Improper Integrals
- Inner Product Spaces, Gram-Schmidt, Projections and Adjoints
- Lax--Milgram and Weak Elliptic Solutions
- Lebesgue Measure on Euclidean Space
- Limits of Real Functions
- limsup, liminf, and Subsequential Limits
- Line Integrals and the Gradient Theorem
- Linear Independence, Bases and Dimension
- Linear Transformations, Rank-Nullity and Quotient Spaces
- Matrices, the Matrix of a Linear Map, and Change of Basis
- Measurable Functions and Simple Approximation
- Measures and Their Basic Properties
- Metric Spaces
- Mixed Partials, Taylor Formulae, and Extrema
- Modes of Convergence Egorov and Lusin
- Modules, Submodules, Quotient Modules and the Isomorphism Theorems
- Monotone Functions, Discontinuities, and Continuity Sets
- Monotone Sequences, Bolzano-Weierstrass, and Cauchy Completeness
- Normal Subgroups and Quotient Groups
- Normed and Banach Spaces
- Norming and Separation under Hahn–Banach
- Operator domains, deficiency spaces and boundary realizations
- Order, Zorn's Lemma, and the Axiom of Choice
- Ordinal Arithmetic and the First Uncountable Ordinal
- Ordinals, Cardinals, and Transfinite Recursion
- Orthonormal Bases, Parseval and Fourier Series
- Outer Measure and the Caratheodory Extension Theorem
- Partitions of Unity and Paracompactness
- pi: the Equivalent Characterizations
- Pointwise Extended-Real Function Products
- Polynomial Rings, the Division Algorithm and Roots
- Power Series and Real-Analytic Functions
- Product Measures and the Fubini Tonelli Theorems
- Properties of the Integral and the Working FTC
- Qm Math Composites
- Qm Math Coulomb
- Qm Math Intervals And Contacts
- Qm Math Magnetic And Detection
- Qm Math Oscillator
- Radon Measures and the Riesz Markov Kakutani Theorem
- Regular Surfaces and Surface Integrals
- Relations, Functions, and Quotients
- Rings, Subrings, Integral Domains and Fields
- Rⁿ as a Normed Space; Vector-Valued Functions
- Roots, Rational Powers, and Classical Inequalities
- Schwartz Space and the Plancherel Theorem
- Semibounded forms, variational spectra and Birman–Schwinger
- Separation Axioms: the Hierarchy
- Sequences and Limits
- Sequences and Series of Functions; Uniform Convergence
- Series: Convergence and the Nonnegative Tests
- Sigma Algebras and Borel Sets
- Signed and Complex Measures Hahn and Jordan
- Simple Field Extensions and the Construction of the Complex Numbers
- Sine, Cosine, and the Definition of Pi
- Smooth Approximation and Sobolev Extension
- Smooth Partitions of Unity and Exhaustions
- Spectral Measures and Borel Functional Calculus
- Stone–Weierstrass in General
- Strongly Continuous Semigroups and Hille Yosida
- Subspaces, Products, and Quotients
- Suprema and Infima
- Symmetric Groups, Cycle Decomposition and the Sign Homomorphism
- Tensor Products of Modules
- The Analytic Hahn Banach Theorem
- The Baire Principles of Functional Analysis
- The Cantor Set, Baire Category, and Measure Zero in ℝ
- The Complex Exponential and Euler's Formula
- The Derivative and the Mean Value Theorems
- The Divergence Theorem and Classical Stokes
- The Exponential Function
- The Fundamental Theorems of Calculus
- The Inverse and Implicit Function Theorems
- The Inverse Function Theorem Completed
- The Lebesgue and Riemann Integrals Compared
- The Lebesgue Integral and the Convergence Theorems
- The Logarithm and General Powers
- The Lᵖ Spaces Holder Minkowski and Riesz Fischer
- The Maximal Function and Lebesgue Differentiation
- The Radon Nikodym Theorem and Lebesgue Decomposition
- The Riemann Integral in Rᵐ and Jordan Content
- The Riemann Integral: Definition and Integrability
- The Topology of Euclidean Space
- The Total Derivative in ℝᵐ → ℝⁿ
- The ZFC Axioms and the Basic Set Constructions
- Topological Spaces and Continuity
- Topology of ℝ
- Triangularisation, Generalised Eigenspaces and Jordan Canonical Form
- Unbounded Self Adjoint Operators and Stones Theorem
- Urysohn's Lemma and the Tietze Extension Theorem
- Vector Spaces, Linear Subspaces, Span and Direct Sums
- Weak Derivatives and Sobolev Spaces
2 · Summary
This page develops three related pieces of magnetic nonrelativistic quantum mechanics under explicit model assumptions: the closed-form treatment of a smooth vector potential that may grow at infinity, the topology of flux on an ideal periodic ring, and the formal spin-half Pauli coupling. The SI minimal-coupling convention is . In the planar Landau formulas, for , denotes the scalar perpendicular component , . In the three-dimensional Pauli model, for , is the curl vector .
The mathematical carrier starts with Magnetic quadratic-form data and Closability of smooth magnetic forms with locally integrable potentials. They define the magnetic quadratic form on and establish its closability for smooth real and a real locally integrable scalar potential bounded below. The proof treats the covariant derivatives as symmetric core operators and uses the weak derivative criterion for closability. It does not assume that is bounded. For the linear Landau gauge the form route is essential: is unbounded, so the bounded-coefficient realization does not apply.
For a constant perpendicular field, Closed-form diagonalization in Landau gauge constructs the partial Fourier and translation unitary and diagonalizes the closed form into oscillator fibers with an unrestricted degeneracy variable. Exact planar Landau spectrum in the linear gauge then identifies the exact infinite-plane spinless spectrum conditionally on the stated form representation input. The infinite multiplicity is exact for this ideal plane model; no finite-area or finite-sample state count is asserted.
Closed-form diagonalization with free longitudinal motion proves that adding a free longitudinal coordinate adds the multiplier to each transverse band, including the required weighted-form density and closure argument. Its physical consequence is worked out on the companion page.
The ring section fixes the periodic Sobolev domain in Periodic Sobolev domain for a circle and proves the shifted Fourier spectrum in Spectrum and gauge periodicity of a periodic flux operator. Under the adopted zero-width ring constraint, Aharonov–Bohm ring spectrum and flux periodicity gives the energy levels and periodicity under one flux quantum. The theorem's Remarks fix the loop orientation and circulation convention. The calculation does not model a finite-width ring or an apparatus.
Finally, Unbounded vector potential and effective Pauli model states the SI minimal-coupling model and an optional effective spin-half form. The core algebra in Pauli square identity and the formal g=2 coupling yields the formal coefficient in that effective model. It is not a measured electron -factor, and the core identity does not assert a closed-domain identity or a relativistic correction.
3 · Logical flowchart
4 · Definitions, postulates, theorems and proofs
Magnetic quadratic-form data
Definition
Assume Countable Choice and let be an integer. Work in with , linear in the first variable, using the quotient and complex-function conventions of the linked Euclidean definitions. Fix real scalars , , and . Let be real and let satisfy almost everywhere for some finite . Put and, for , define For define the sesquilinear form and write . Each integral is finite: the test functions and their magnetic derivatives are bounded with compact support, and is integrable on compact sets. The form is Hermitian, densely defined, and bounded below by .
For define its shifted form norm by The form is closable when every sequence with and as also satisfies . This condition is independent of the choice of . When it holds, the closed form closure is the completion of in this norm, identified with its limits; the corresponding closed form is denoted .
Periodic Sobolev domain for a circle
Definition
Assume the Axiom of Choice and Countable Choice. Let with angular coordinate , and identify with ; the omitted endpoint has measure zero. Let be the interval Sobolev space whose elements and first two weak derivatives are in . For use the continuous endpoint representatives of and , and denote their traces by and . Define the periodic second-order domain It is the domain used for the periodic realization of the second derivative; it imposes no boundary at the angular seam beyond periodic matching.
Closability of smooth magnetic forms with locally integrable potentials
Statement
Assume Countable Choice and Dependent Choice. Let and be the magnetic form on the test core, with , , real-valued and almost everywhere. Then is closable on in the shifted form norm for every . Its closure is a densely defined closed Hermitian form bounded below by .
Statement references
Facts & Assumptions
Given: Countable Choice, Dependent Choice, , , real , smooth real , real with , and the core form .
Countable Choice and Dependent Choice are the assumptions of the Hilbert-space, Fubini, and compact-interval integration-by-parts inputs (The Axiom of Countable Choice (), The axiom of dependent choice: a relation in which every element is related to something admits an -indexed chain).
The complex pairing is a Hilbert inner product, is dense in , and Cauchy–Schwarz holds. The weak-derivative convention uses this same quotient space (Magnetic quadratic-form data, Position and momentum operators on Euclidean L2, Cauchy-Schwarz inequality for ).
Each maps the core to itself and is symmetric there. On a compact rectangle this follows from one-variable integration by parts on each coordinate slice, Fubini, and the reality of (Integration by parts for absolutely continuous functions, Fubini's theorem for L^1 functions on a sigma-finite product).
If , then , , and for every : on a compact support, is bounded and (Magnetic quadratic-form data).
Proof
Fix and put . For every , This identity shows that if is Cauchy in the shifted form norm, then each sequence and is Cauchy in .
Suppose additionally that . Let be the limit of . For any , symmetry [F2] and Cauchy–Schwarz give Density in [F1] implies . If is the limit of , then [F3] and Cauchy–Schwarz similarly give for every test function , so density gives .
Every term on the right side of the norm identity in step 1.1 therefore tends to zero, including . Thus , which is exactly the closability criterion in Magnetic quadratic-form data. The completion is densely embedded in because it contains the dense core, and the criterion makes that embedding injective; its form is closed by construction and retains the lower bound .
Closed-form diagonalization in Landau gauge
Statement
Assume Countable Choice and Dependent Choice, , and real with . On close the nonnegative form Put , , and let be the complete normalized eigenfunctions of the one-dimensional oscillator with mass , frequency , and action constant in its exact self-adjoint oscillator realization. For Schwartz define , and use its unitary extension. Put and . Then is unitary from onto . Writing the form closure domain and value are exactly Thus the form is the diagonal oscillator form with an unrestricted degeneracy factor; it asserts no finite-area state count.
Statement references
Facts & Assumptions
Given: Countable Choice and Dependent Choice, , , the form , and the oscillator eigenfamily with energies .
The magnetic form on is the form of Magnetic quadratic-form data with , and .
The -frequency Fourier transform on has kernel (Fourier transform on complex L1 classes), and its extension to is unitary (Plancherel theorem). The wave-number convention in the Statement is the unitary rescaling ; for Schwartz it satisfies by integration by parts, and Fourier transform preserves Schwartz space (Fourier transform is a topological automorphism of Schwartz space). The Euclidean product identification and Fubini apply (Euclidean L² product unitary: L²(R^a)⊗̂L²(R^b) ≅ L²(R^{a+b}), Fubini's theorem for L^1 functions on a sigma-finite product); the integration-by-parts identity used for the derivative multiplier is Integration by parts for absolutely continuous functions.
For , let be the exact self-adjoint oscillator realization in Oscillator scaling and exact realization. It has complete orthonormal basis , eigenvalues , and domain On its polynomial-Gaussian core it has differential expression ; in particular, on that core.
Translation of one Lebesgue variable preserves its integral, and integration by parts holds for smooth compactly supported functions (A C^1 diffeomorphism satisfies the change-of-variables formula for L^1 functions, Integration by parts for absolutely continuous functions).
Smooth compactly supported cutoffs equal to one on expanding balls and with first derivatives bounded by are obtained by rescaling the standard smooth step function (The standard smooth step function).
Tonelli's theorem permits integration of the nonnegative oscillator energy series term by term over with Lebesgue measure (Tonelli's theorem for nonnegative measurable functions on a sigma-finite product).
For every finite and dimension, compactly supported smooth functions are dense in ; in particular this holds for (Compactly supported smooth functions are dense in W^{k,p}(R^n)).
The weighted sequence space in the Statement is complete: it is on for the sigma-finite measure , and of any measure space is Hilbert under Countable Choice ( with the integral pairing is a Hilbert space).
On any measure space, measurable complex-valued functions converging almost everywhere and bounded in modulus by a single nonnegative measurable function converge in integral (indeed in ). Dominated convergence
Countable Choice is assumed by the unitary Fourier, product-space, and oscillator suppliers; Dependent Choice is an exact hypothesis of the absolutely-continuous integration-by-parts supplier (The Axiom of Countable Choice (), The axiom of dependent choice: a relation in which every element is related to something admits an -indexed chain, Integration by parts for absolutely continuous functions).
Proof
On the dense tensor core with , is the identity on the first factor and the unitary Fourier transform on the second, by [F2] and the Euclidean product identification in [F2]. It extends uniquely to a unitary on . For each , translation preserves the -integral by [F4]; Fubini then shows that is an isometry with inverse . Hence is unitary.
Let and write . For each fixed , is smooth and compactly supported in . Plancherel in , the derivative identity in [F2], and the substitution give For a compactly supported smooth , put . Integrating by parts twice on a finite interval containing the support of gives , since and the boundary terms vanish. Completeness and Parseval therefore give The exact domain characterization in [F3] now implies , and its diagonal action gives . Hence Integration by parts also identifies the left side with Apply this identity to for almost every . Tonelli [F6] permits integrating the nonnegative series, so the displayed core form is the coefficient form on every transformed core vector.
For and , has inverse Write . The integrands have compact -support and are Schwartz in uniformly there by the Hermite form in [F3]; differentiating under the integral and integrating by parts in show rapid decay in , so the inverse is Schwartz. Define using [F5]. These cutoffs are one on , vanish outside , and have . For each covariant derivative, Take integer . The step-function bounds in [F5] give , and for every fixed , once , so pointwise. Since is Schwartz and is linear, and are Schwartz and belong to . For each , the functions are measurable, tend pointwise to zero, and are bounded by the single measurable majorant . Applying [F9] on the Lebesgue measure space gives . The derivative-cutoff term separately satisfies . Thus the displayed product identity and the triangle inequality give for both , as well as . The form identity of step 2.1 also holds for Schwartz functions: the Fourier and shear maps preserve Schwartz regularity, and for each Schwartz one has ; its integration-by-parts pairings with the polynomial-Gaussian have vanishing boundary terms at both infinities. The same Parseval calculation and exact diagonal operator-domain criterion in [F3] therefore give and the same oscillator energy identity. All resulting nonnegative energies can again be integrated by [F6]. Apply this extended identity to the Schwartz difference . Its weighted coefficient norm squared is exactly , which tends to zero by the preceding bounds. Since , each therefore lies in the weighted-norm closure of the transformed original core, without assuming closability in advance. Finite coefficient families are dense in the weighted target: truncate its convergent nonnegative series, then approximate the remaining finitely many coefficients by using [F7].
Let be the coefficient space with squared norm , and let be the identity inclusion. Step 2.1 maps the transformed core isometrically into . Since , is continuous and injective, with . The coefficient map is unitary on the underlying space by [F2] and [F3]. Thus on the core. For every , so each shifted form norm is equivalent to . Suppose a core sequence is Cauchy in and tends to zero in . Its weighted coefficient image converges in to some ; unweighted convergence and continuity of give . Injectivity of gives , so along that sequence. The equivalence above then gives convergence to zero in the defining shifted form norm, proving closability of the core form. By [F8] the target is complete, so the isometric image of the form completion is closed there. Step 3.1 places a dense subspace of that target in the image; hence the image is the whole weighted space and the form closure is exactly the stated one.
Remarks
The diagram records the unitary changes of representation used in the proof; the argument establishes each arrow and does not rely on the diagram.
Here is the coefficient map , which is unitary by the complete oscillator basis. The linear Landau potential is unbounded, so no bounded-coefficient realization is invoked.
Spectrum and gauge periodicity of a periodic flux operator
Statement
Assume the Axiom of Choice, Countable Choice, and Dependent Choice. Let and . On use the periodic domain defined by periodic endpoint traces and define Then is self-adjoint and the normalized characters , , form a complete orthonormal eigenbasis with eigenvalues . Its spectrum is the closed set and its spectral measures are purely atomic on that set. For every , multiplication by unitarily intertwines with . A smooth periodic unit-modulus function satisfying exists exactly when .
Statement references
Facts & Assumptions
Given: the Choice, Countable Choice, and Dependent Choice axioms; , , the Hilbert space , and the periodic domain in the Statement.
The Choice, Countable Choice, and Dependent Choice hypotheses are those of the interval realization, Fourier-basis, Kato–Rellich, and unbounded spectral suppliers (The Axiom of Choice, The Axiom of Countable Choice (), The axiom of dependent choice: a relation in which every element is related to something admits an -indexed chain).
For , the periodic endpoint traces are those of Periodic Sobolev domain for a circle. The interval Laplacian with the swap matrix has exactly these periodic boundary conditions and is self-adjoint by All self-adjoint interval Laplacian boundary conditions.
The characters form a complete orthonormal basis of , where has normalized Haar probability measure (Fourier coefficients and trigonometric polynomials on the torus, The trigonometric system is complete in of the torus). The map is unitary: in the fundamental-domain coordinate , and its inverse is almost everywhere. Moreover . Thus the exact characters in the Statement are a complete orthonormal basis for the stated Lebesgue measure convention.
If is self-adjoint and is symmetric on with for some , then on is self-adjoint (Kato-Rellich theorem, Relative boundedness with respect to an operator).
A self-adjoint operator has a unique regular spectral projection-valued measure, and its domain and spectral integrals are given by the unbounded spectral theorem (Spectral theorem for unbounded self-adjoint operators (PVM form)). For any self-adjoint with a complete orthonormal eigenbasis and eigenvalues , this gives spectral projections equal to sums of the rank-one projections onto the and On this domain, in .
Integration by parts on the interval holds for the periodic Sobolev functions and their endpoint traces; in particular is symmetric on the stated domain (Integration by parts and the endpoint-vanishing space on intervals).
Proof
Set on . In the boundary coordinates and , the unitary swap matrix in [F1] makes the boundary equation equivalent to and : adding and subtracting its two scalar equations gives these two equalities. Hence is self-adjoint on this domain, and multiplication by the positive real shows that is self-adjoint. Let . Integration by parts [F5] and equality of the endpoint traces show that is symmetric on . For in this domain, integration by parts gives and . Parseval for [F2] therefore implies and .
On write with . This operator is symmetric because is symmetric and are real. For every and integer , ; the coefficient identities in step 1.1 and the triangle inequality give with any prescribed after choosing sufficiently small and then a finite . Applying [F3] with proves that is self-adjoint on the stated periodic domain.
Each lies in the periodic domain and direct differentiation gives . Completeness [F2] makes this the full orthonormal eigenbasis. The associated spectral projections are therefore the sums of the character projections whose eigenvalues lie in the chosen Borel set, so every scalar spectral measure is supported on . This set has no finite accumulation point because and . If is outside it, . For , where , the diagonal map is bounded on . Also , so the domain characterization in [F4] shows that maps into . Coefficientwise, and on , so is in the resolvent. If then is a nonzero kernel vector. Hence the spectrum is exactly the displayed set and there is no continuous spectral measure.
Let and . It is unitary, preserves the periodic domain, and by differentiation; squaring gives . If a smooth periodic unit-modulus function satisfies the displayed conjugacy, then , or . The solutions are with , which are periodic exactly when , equivalently . Conversely, for integral this multiplier is single-valued and periodic.
Remarks
The diagram expresses the integer-flux unitary intertwining. Its arrow labels are the multiplication operators proved in step 4.1; the proof above is independent of the diagram.
Closed-form diagonalization with free longitudinal motion
Statement
Assume Countable Choice and Dependent Choice, , and real with . Let , , and for . On close the nonnegative form Use the wave-number Fourier convention and set Then extends to a unitary map onto by expansion in the complete transverse oscillator basis . If the form closure domain and value are exactly
Statement references
Facts & Assumptions
Given: Countable Choice and Dependent Choice, , real with , and the three-dimensional core form in the Statement.
Countable Choice is the hypothesis of the transverse form, product Fourier, and compactly-supported density inputs. The transverse form lemma also assumes Dependent Choice because its integration-by-parts supplier does (The Axiom of Countable Choice (), The axiom of dependent choice: a relation in which every element is related to something admits an -indexed chain, Closed-form diagonalization in Landau gauge).
The displayed core form is the , instance of the magnetic form definition; in the planar core form closes to the oscillator coefficient form with energies and complete normalized functions (Magnetic quadratic-form data, Closed-form diagonalization in Landau gauge).
The partial Fourier transforms in are unitary on and send to multiplication by on Schwartz functions; the product-space identifications and their iterated use are valid (Fourier transform on complex L1 classes, Plancherel theorem, Fourier transform is a topological automorphism of Schwartz space, Euclidean L² product unitary: L²(R^a)⊗̂L²(R^b) ≅ L²(R^{a+b}), Integration by parts for absolutely continuous functions).
Translation of the variable preserves Lebesgue measure (A C^1 diffeomorphism satisfies the change-of-variables formula for L^1 functions).
is dense in , and smooth cutoffs equal to one on expanding boxes with first derivatives bounded by can be built from the standard smooth step function (Compactly supported smooth functions are dense in W^{k,p}(R^n), The standard smooth step function).
Fubini and Tonelli apply to Lebesgue product spaces, including the nonnegative oscillator-energy series (Fubini's theorem for L^1 functions on a sigma-finite product, Tonelli's theorem for nonnegative measurable functions on a sigma-finite product).
The weighted coefficient space is complete: identify it with on for the measure . This measure is sigma-finite because the weight is finite on each bounded box and finite index set, and on a measure space is Hilbert under Countable Choice ( with the integral pairing is a Hilbert space).
The oscillator eigenfunctions are normalized Hermite functions, hence polynomial times Gaussian and Schwartz (Oscillator scaling and exact realization).
Dominated convergence applies to the integrable weighted coefficient tails and to the tails of Schwartz functions (Dominated convergence).
Proof
First apply the unitary planar map from [F1] at each fixed , then the partial Fourier transform in from [F2]. On the dense product core both maps are unitary; the Euclidean product identifications in [F2] extend their composition uniquely to a unitary on . The inverse uses the inverse Fourier transforms and the opposite translation, which is measure preserving by [F3]. The coefficient map in the transverse variable is unitary because is a complete orthonormal basis. Thus is unitary onto the stated coefficient space.
Let have finite weighted norm and fix . Since the defining nonnegative series converges, choose so the norm of its tail over is below . For the finitely many indices , the weighted integrals outside tend to zero as by dominated convergence, so choose one making their combined tail norm below . Define It equals one on , is between zero and one, and has support in by [F4]. For each , truncate to and approximate that truncation in unweighted by using [F4]. The function is smooth and supported in , and on that box . Since on and , choose each of the finitely many errors small enough that the weighted norm difference between and the truncation has combined norm below . Set for . The triangle inequality then gives a finite family within of in the weighted coefficient norm.
For , every -slice is a planar test function. Apply the form identity in [F1] on those slices and integrate in by Fubini. The derivative commutes with the planar transform; after Fourier transformation in , Plancherel and the derivative identity in [F2] turn into the multiplier . Tonelli [F5] permits summing the nonnegative transverse energies and integrating in . Therefore This makes the transformed core an isometric subspace of the stated weighted coefficient space.
For the finite family from step 1.2 put . Its inverse is Each coefficient is smooth and compactly supported in , and each is a polynomial times a Gaussian by [F7]. Every derivative of the integrand is smooth with compact wave-number support and has uniformly rapid decay in because remains in a bounded set. Repeated integration by parts in gives arbitrary polynomial decay in ; the same estimates hold after any fixed derivatives. Thus is Schwartz. Define using the smooth step from [F4]. These cutoffs equal one on , vanish outside , and satisfy . For each covariant derivative, where , , and . Dominated convergence [F8] sends and to zero in , while the added term has norm at most . Hence approximates in the form norm and belongs to the original compactly supported core. Thus each finite smooth coefficient family from step 1.2 lies in the transformed form closure.
Step 2.1 embeds the transformed core isometrically into the weighted coefficient space. Because the form completion is complete and the weighted target is complete by [F6], the isometric image of the completion is closed in that target. Steps 1.2 and 2.2 show that a dense subspace of the entire weighted space lies in the image, so the image is the whole target. This identifies the completion and its quadratic form as stated.
Unbounded vector potential and effective Pauli model
A nonrelativistic point-particle model with a static smooth external vector potential and locally integrable lower-bounded scalar potential on Euclidean R^d, d >= 1, in SI units. The planar field is the scalar perpendicular component and the three-dimensional field is the curl vector. The optional spin-half Pauli coupling is a three-dimensional effective model term only when its form is closable and semibounded; no measured g-factor or relativistic correction is asserted.
Postulate
Use SI units with mass in kilograms, charge in coulombs, action constant in joule-seconds, vector-potential components in tesla-metres, and scalar potential-energy function in joules. For each integer , let be real and let be bounded below. Adopt the general-dimensional minimal-coupling assignment whose core form is Use its closed form closure and the unique self-adjoint representing Hamiltonian. For dimensional form norms use the fixed reference energy : apply the closed-form representation to and multiply the representing operator by .
The magnetic-field notation is dimension-specific. In , with coordinates and , define the scalar perpendicular field in teslas. Thus gives for a constant signed scalar . In , for coordinates and , define the field vector in teslas by No magnetic-field object is assigned by this notation in .
For an optional spin-half degree of freedom in three dimensions, define For a core spinor , define the spin-independent form For a declared dimensionless real coupling , adopt the effective Pauli core form where is conjugate transpose and for the three-dimensional field vector just defined. Include this term only in model instances where the resulting form is closable and bounded below, and use its closed form closure and representing Hamiltonian. No universal semiboundedness for arbitrary is asserted.
Postulate references
Scope and non-derivation
The core form data and the closability argument are given in Magnetic quadratic-form data and Closability of smooth magnetic forms with locally integrable potentials. The form-representation interface Semibounded closed-form representation and perturbation specifies the unique self-adjoint operator associated with the adopted closed form. The generic closability supplier assumes Countable Choice and Dependent Choice; the representation supplier assumes the Axiom of Choice and Countable Choice. These are the mathematical hypotheses of the construction, not additional physical postulates.
The mathematical identity in Pauli square identity and the formal g=2 coupling is a formal-core identity. This postulate does not identify with an electron measurement, derive the anomalous magnetic moment, or use the Dirac or quantum-electrodynamic theories. The linear Landau gauge is covered by the local closed-form construction; no bounded-coefficient hypothesis is imposed.
Exact planar Landau spectrum in the linear gauge
Exact spectral prediction of the adopted spinless nonrelativistic point-particle model on the infinite plane, for a constant nonzero perpendicular field in the unbounded linear Landau gauge. It makes no finite-sample degeneracy count, boundary claim, or empirical assertion.
Statement
Assume the Axiom of Choice, Countable Choice, and Dependent Choice, and the adopted spinless minimal-coupling form model. Let be mass in kilograms, charge in coulombs, the constant signed perpendicular field component in teslas, and in joule-seconds. Let be in tesla-metres; then is its scalar perpendicular field. Take wavefunctions in . Set and define the Hamiltonian by the closed form of the core expression The resulting Friedrichs Hamiltonian is unitarily equivalent, under partial Fourier transformation in followed by , to the constant family of oscillators with its form-closed realization. Its spectrum is Every listed eigenvalue has infinite multiplicity, and every spectral measure is purely atomic on this set; there is no continuous spectral measure. This is a conditional model deduction, not a claim that a material realizes the ideal infinite-plane Hamiltonian.
Statement references
Facts & Assumptions
Given: the Axiom of Choice, Countable Choice, Dependent Choice, the spinless model postulate, , , , , , and the core form in the Statement. Use SI units.
Adopt the spinless minimal-coupling assignment and the stated Friedrichs-form prescription (Unbounded vector potential and effective Pauli model).
The Axiom of Choice and Countable Choice are hypotheses of the closed-form representation and unbounded spectral suppliers. Dependent Choice is required by the Landau form supplier (The Axiom of Choice, The Axiom of Countable Choice (), The axiom of dependent choice: a relation in which every element is related to something admits an -indexed chain, Closed-form diagonalization in Landau gauge).
The closed magnetic form is unitarily equivalent to the diagonal form on coefficient families, with , under the explicitly normalized partial Fourier and translation map (Closed-form diagonalization in Landau gauge).
The closed-form representation theorem applies to a dimensionless closed form. Write for the postulate's reference energy and apply the theorem to . On the closed form domain, , so normalization preserves its form domain, density, and closedness. The theorem's operator domain consists of form-domain vectors for which there is a coefficient-space vector satisfying for every form-domain vector . If represents this normalized form, then the model Hamiltonian is on the same operator domain, so its spectral values are multiplied by . Here is distinct from the indexed Landau level used below. The theorem's exact hypotheses include the Axiom of Choice and Countable Choice (Unbounded vector potential and effective Pauli model, Semibounded closed-form representation and perturbation).
The one-dimensional oscillator with has the complete Hermite eigenbasis and eigenvalues (Oscillator scaling and exact realization).
A self-adjoint operator has a unique regular spectral projection-valued measure (Spectral theorem for unbounded self-adjoint operators (PVM form)).
Proof
The hypotheses and make and the translation well-defined. Apply [F1]: the unitary sends the closed form to the coefficient form where and is the complete oscillator basis from [F3]. In particular, for nonzero .
Apply the closed-form representation theorem [F2] to the normalized form . If is in its representing operator domain, there is in the coefficient Hilbert space such that for every form-domain vector . Fix and take to have sole nonzero component . It lies in the form domain because and is finite. The representation identity gives so for every . Since belongs to the Hilbert space, , equivalently because .
Conversely, suppose is in the form domain and . Define , which is a vector in the coefficient Hilbert space. For every form-domain vector , Cauchy–Schwarz gives absolute convergence and Thus [F2] represents the normalized operator by on the stated domain. The model Hamiltonian is times this operator and therefore acts by on that same domain; uniqueness identifies it with the postulated Hamiltonian.
For each , the eigenspace at is , which is infinite-dimensional; the energies are strictly increasing and tend to . If , then and . The diagonal inverse is therefore bounded and maps into the operator domain, so is in the resolvent. Each is an eigenvalue, and the complete coefficient decomposition together with [F4] shows that all spectral projections are sums of eigenspace projections. Hence every spectral measure is atomic on the displayed set and the spectrum is exactly that set.
Remarks
The linear potential is unbounded. The proof works with its closable quadratic form and never applies a bounded-coefficient realization. The finite-rectangle degeneracy count in the cited treatments depends on boundary conditions; no exact hard-wall or finite-area count is claimed here.
Aharonov–Bohm ring spectrum and flux periodicity
Exact spectrum of an ideal spinless particle constrained to a zero-width circle with static enclosed magnetic flux and periodic wavefunctions. Finite-width rings, interactions, apparatus, and experimental identification are outside scope.
Statement
Adopt the static ring model of a spinless particle of mass kilograms and charge coulombs constrained to a circle of radius metres. Use in joule-seconds, flux in webers, and energies in joules. The angular coordinate is ; the single-valued wavefunction belongs to the periodic domain ; the scalar potential is zero; and a static tangential vector potential has circulation , where is flux in webers. Under the SI minimal-coupling assignment, the Hamiltonian is on that periodic domain. Its energies are with a complete periodic Fourier eigenbasis. For every , gives a unitarily equivalent Hamiltonian; a noninteger cannot be removed by a single-valued periodic gauge phase. These are conditional deductions of the ideal ring model.
Statement references
Facts & Assumptions
Given: the ideal ring constraint, , , , , static flux , zero scalar potential, periodic wavefunctions, and the SI minimal-coupling postulate.
The ring is an ideal zero-width constraint with no radial or transverse degrees of freedom. The model adopts a single-valued periodic wavefunction and the periodic realization of the tangential minimal-coupling expression; the static flux is represented by .
The Choice, Countable Choice, and Dependent Choice axioms are the exact mathematical hypotheses of the periodic spectral calculation (The Axiom of Choice, The Axiom of Countable Choice (), The axiom of dependent choice: a relation in which every element is related to something admits an -indexed chain).
The minimal-coupling covariant momentum is in SI units; is the mass parameter and the charge parameter (Unbounded vector potential and effective Pauli model).
The angular Hilbert space and periodic domain are those of Periodic Sobolev domain for a circle.
For and , the operator has complete eigenbasis , energies , integer-shift unitary equivalence, and no periodic gauge multiplier removing a noninteger (Spectrum and gauge periodicity of a periodic flux operator).
Proof
On the circle, arclength is , so the tangential derivative is . The circulation of the constant tangential potential is by [A1]. Therefore the covariant tangential momentum supplied by [F1] is Dividing its square by gives the Hamiltonian in the Statement and the dimensionless parameter .
Put . The operator in the Statement is , so [F2] and [F3] give its periodic domain, complete Fourier eigenbasis, energy list, and spectrum. If the flux is shifted by , then shifts by and the unitary multiplication intertwines the two Hamiltonians by [F3]. The same fact [F3] shows that a smooth single-valued periodic phase removing exists only for integral . Thus the spectrum and its gauge periodicity follow conditionally from the declared ideal ring model; no finite-width correction or measurement is asserted.
Remarks
The loop orientation is increasing , and positive flux means the circulation in that orientation. The figure is a schematic of the excluded flux core and the constrained path; it is not a geometrical proof of the spectral statement.
Pauli square identity and the formal g=2 coupling
Formal differential-operator identity on compactly supported two-component spinors for a smooth static SI vector potential in three-dimensional nonrelativistic Pauli-model kinematics. It asserts neither a closed-domain identity nor a measured particle g-factor.
Statement
Let be mass in kilograms, charge in coulombs, in joule-seconds, and let be a real SI vector potential in tesla-metres, with in teslas. On the two-component core define . With the spin-half matrices and fixed in the effective Pauli model, the following identity holds on that core: Consequently the quadratic Pauli expression equals the minimally coupled kinetic expression plus the spin term , which is the formal effective Pauli coupling at . This is a core identity only; it makes no claim about closed operator domains or the measured magnetic moment of an electron.
Statement references
Facts & Assumptions
Given: the effective spin-half model, , real , , smooth real , , and compactly supported smooth two-component spinors.
The spin matrices are and is a declared real dimensionless effective coupling (Unbounded vector potential and effective Pauli model).
On the test core, ; the curl convention is (Magnetic quadratic-form data, Divergence and curl of a vector field).
The ordinary product rule holds for the smooth coefficient products (Sums, scalar multiples, products and quotients: , , , and when ).
Proof
Direct multiplication of the matrices in [A1] gives for each , , , , and the reversed products have the opposite sign. Hence For a core spinor , the product rule [F2] and the definition of give All terms remain compactly supported smooth spinors.
Since the Pauli matrices act only on the spin factor, they commute with each . Expanding the square using step 1.1 gives Substitute the commutator from step 1.1. The finite identity follows by listing the two nonzero ordered pairs when and none when ; the resulting term is . This proves the displayed Pauli square.
Dividing by and using from [A1] rewrites the spin term as . Comparison with the adopted coupling identifies its formal coefficient as . The conclusion is only the stated identity of core differential expressions; the postulate separately requires a closable semibounded form before assigning a self-adjoint Pauli Hamiltonian.
5 · Examples, experiments and counterexamples
None yet.
Sources
- David Tong, Applications of Quantum Mechanics, §1.1.1, magnetic Hamiltonian and gauge conventions
- V. P. Nair, Notes on Quantum Mechanics, §§11.3 and 13.1–13.2, Pauli and magnetic Hamiltonian conventions
- Gerald Teschl, Mathematical Methods in Quantum Mechanics, 1st edition, Chapter 9, interval Sobolev domains and boundary traces
- V. P. Nair, Notes on Quantum Mechanics, §13.1, particle configuration with a flux tube removed
- Gerald Teschl, Mathematical Methods in Quantum Mechanics, 1st edition, §2.3, closed forms and Friedrichs construction
- David Tong, Applications of Quantum Mechanics, §1.2, constant-field magnetic quadratic expression
- David Tong, Applications of Quantum Mechanics, §1.2, Landau gauge and oscillator fibers
- Aram Harrow, MIT 8.06 Spring 2016 Lecture Notes, Chapter 4, §§3.1–3.2
- V. P. Nair, Notes on Quantum Mechanics, §13.2
- David Tong, Applications of Quantum Mechanics, §1.3.1, particle on a ring around a flux tube
- V. P. Nair, Notes on Quantum Mechanics, §13.1, Aharonov–Bohm flux and phase
- David Tong, Applications of Quantum Mechanics, §1.2, Landau levels with longitudinal momentum
- V. P. Nair, Notes on Quantum Mechanics, §13.2, longitudinal momentum bands
- David Tong, Applications of Quantum Mechanics, §§1.1.1 and 1.5, minimal coupling and spin in a magnetic field
- V. P. Nair, Notes on Quantum Mechanics, §§11.2–11.3, spin magnetic moment and Pauli equation
- Aram Harrow, MIT 8.06 Spring 2016 Lecture Notes, Chapter 4, §3.1, charged-particle Hamiltonian
- David Tong, Applications of Quantum Mechanics, §1.2, Landau gauge and Landau levels
- V. P. Nair, Notes on Quantum Mechanics, §13.2, uniform-field Landau levels
- Aram Harrow, MIT 8.06 Spring 2016 Lecture Notes, Chapter 4, §3.2, Landau levels
- David Tong, Applications of Quantum Mechanics, §1.3.1, the flux-threaded ring
- V. P. Nair, Notes on Quantum Mechanics, §13.1, flux and the Aharonov–Bohm phase
- Aram Harrow, MIT 8.06 Spring 2016 Lecture Notes, Chapter 4, §3.5, Aharonov–Bohm effect
- V. P. Nair, Notes on Quantum Mechanics, §11.3, Pauli equation and commutator expansion
- David Tong, Applications of Quantum Mechanics, §1.5.2, spin and Zeeman coupling