Metamath Proof Explorer


Theorem kbpj

Description: If a vector A has norm 1, the outer product | A >. <. A | is the projector onto the subspace spanned by A . http://en.wikipedia.org/wiki/Bra-ket#Linear%5Foperators . (Contributed by NM, 30-May-2006) (New usage is discouraged.)

Ref Expression
Assertion kbpj ( ( 𝐴 ∈ ℋ ∧ ( norm𝐴 ) = 1 ) → ( 𝐴 ketbra 𝐴 ) = ( proj ‘ ( span ‘ { 𝐴 } ) ) )

Proof

Step Hyp Ref Expression
1 oveq1 ( ( norm𝐴 ) = 1 → ( ( norm𝐴 ) ↑ 2 ) = ( 1 ↑ 2 ) )
2 sq1 ( 1 ↑ 2 ) = 1
3 1 2 eqtrdi ( ( norm𝐴 ) = 1 → ( ( norm𝐴 ) ↑ 2 ) = 1 )
4 3 oveq2d ( ( norm𝐴 ) = 1 → ( ( 𝑥 ·ih 𝐴 ) / ( ( norm𝐴 ) ↑ 2 ) ) = ( ( 𝑥 ·ih 𝐴 ) / 1 ) )
5 hicl ( ( 𝑥 ∈ ℋ ∧ 𝐴 ∈ ℋ ) → ( 𝑥 ·ih 𝐴 ) ∈ ℂ )
6 5 ancoms ( ( 𝐴 ∈ ℋ ∧ 𝑥 ∈ ℋ ) → ( 𝑥 ·ih 𝐴 ) ∈ ℂ )
7 6 div1d ( ( 𝐴 ∈ ℋ ∧ 𝑥 ∈ ℋ ) → ( ( 𝑥 ·ih 𝐴 ) / 1 ) = ( 𝑥 ·ih 𝐴 ) )
8 4 7 sylan9eqr ( ( ( 𝐴 ∈ ℋ ∧ 𝑥 ∈ ℋ ) ∧ ( norm𝐴 ) = 1 ) → ( ( 𝑥 ·ih 𝐴 ) / ( ( norm𝐴 ) ↑ 2 ) ) = ( 𝑥 ·ih 𝐴 ) )
9 8 an32s ( ( ( 𝐴 ∈ ℋ ∧ ( norm𝐴 ) = 1 ) ∧ 𝑥 ∈ ℋ ) → ( ( 𝑥 ·ih 𝐴 ) / ( ( norm𝐴 ) ↑ 2 ) ) = ( 𝑥 ·ih 𝐴 ) )
10 9 oveq1d ( ( ( 𝐴 ∈ ℋ ∧ ( norm𝐴 ) = 1 ) ∧ 𝑥 ∈ ℋ ) → ( ( ( 𝑥 ·ih 𝐴 ) / ( ( norm𝐴 ) ↑ 2 ) ) · 𝐴 ) = ( ( 𝑥 ·ih 𝐴 ) · 𝐴 ) )
11 simpll ( ( ( 𝐴 ∈ ℋ ∧ ( norm𝐴 ) = 1 ) ∧ 𝑥 ∈ ℋ ) → 𝐴 ∈ ℋ )
12 simpr ( ( ( 𝐴 ∈ ℋ ∧ ( norm𝐴 ) = 1 ) ∧ 𝑥 ∈ ℋ ) → 𝑥 ∈ ℋ )
13 ax-1ne0 1 ≠ 0
14 neeq1 ( ( norm𝐴 ) = 1 → ( ( norm𝐴 ) ≠ 0 ↔ 1 ≠ 0 ) )
15 13 14 mpbiri ( ( norm𝐴 ) = 1 → ( norm𝐴 ) ≠ 0 )
16 normne0 ( 𝐴 ∈ ℋ → ( ( norm𝐴 ) ≠ 0 ↔ 𝐴 ≠ 0 ) )
17 15 16 syl5ib ( 𝐴 ∈ ℋ → ( ( norm𝐴 ) = 1 → 𝐴 ≠ 0 ) )
18 17 imp ( ( 𝐴 ∈ ℋ ∧ ( norm𝐴 ) = 1 ) → 𝐴 ≠ 0 )
19 18 adantr ( ( ( 𝐴 ∈ ℋ ∧ ( norm𝐴 ) = 1 ) ∧ 𝑥 ∈ ℋ ) → 𝐴 ≠ 0 )
20 pjspansn ( ( 𝐴 ∈ ℋ ∧ 𝑥 ∈ ℋ ∧ 𝐴 ≠ 0 ) → ( ( proj ‘ ( span ‘ { 𝐴 } ) ) ‘ 𝑥 ) = ( ( ( 𝑥 ·ih 𝐴 ) / ( ( norm𝐴 ) ↑ 2 ) ) · 𝐴 ) )
21 11 12 19 20 syl3anc ( ( ( 𝐴 ∈ ℋ ∧ ( norm𝐴 ) = 1 ) ∧ 𝑥 ∈ ℋ ) → ( ( proj ‘ ( span ‘ { 𝐴 } ) ) ‘ 𝑥 ) = ( ( ( 𝑥 ·ih 𝐴 ) / ( ( norm𝐴 ) ↑ 2 ) ) · 𝐴 ) )
22 kbval ( ( 𝐴 ∈ ℋ ∧ 𝐴 ∈ ℋ ∧ 𝑥 ∈ ℋ ) → ( ( 𝐴 ketbra 𝐴 ) ‘ 𝑥 ) = ( ( 𝑥 ·ih 𝐴 ) · 𝐴 ) )
23 22 3anidm12 ( ( 𝐴 ∈ ℋ ∧ 𝑥 ∈ ℋ ) → ( ( 𝐴 ketbra 𝐴 ) ‘ 𝑥 ) = ( ( 𝑥 ·ih 𝐴 ) · 𝐴 ) )
24 23 adantlr ( ( ( 𝐴 ∈ ℋ ∧ ( norm𝐴 ) = 1 ) ∧ 𝑥 ∈ ℋ ) → ( ( 𝐴 ketbra 𝐴 ) ‘ 𝑥 ) = ( ( 𝑥 ·ih 𝐴 ) · 𝐴 ) )
25 10 21 24 3eqtr4rd ( ( ( 𝐴 ∈ ℋ ∧ ( norm𝐴 ) = 1 ) ∧ 𝑥 ∈ ℋ ) → ( ( 𝐴 ketbra 𝐴 ) ‘ 𝑥 ) = ( ( proj ‘ ( span ‘ { 𝐴 } ) ) ‘ 𝑥 ) )
26 25 ralrimiva ( ( 𝐴 ∈ ℋ ∧ ( norm𝐴 ) = 1 ) → ∀ 𝑥 ∈ ℋ ( ( 𝐴 ketbra 𝐴 ) ‘ 𝑥 ) = ( ( proj ‘ ( span ‘ { 𝐴 } ) ) ‘ 𝑥 ) )
27 kbop ( ( 𝐴 ∈ ℋ ∧ 𝐴 ∈ ℋ ) → ( 𝐴 ketbra 𝐴 ) : ℋ ⟶ ℋ )
28 27 anidms ( 𝐴 ∈ ℋ → ( 𝐴 ketbra 𝐴 ) : ℋ ⟶ ℋ )
29 28 ffnd ( 𝐴 ∈ ℋ → ( 𝐴 ketbra 𝐴 ) Fn ℋ )
30 spansnch ( 𝐴 ∈ ℋ → ( span ‘ { 𝐴 } ) ∈ C )
31 pjfn ( ( span ‘ { 𝐴 } ) ∈ C → ( proj ‘ ( span ‘ { 𝐴 } ) ) Fn ℋ )
32 30 31 syl ( 𝐴 ∈ ℋ → ( proj ‘ ( span ‘ { 𝐴 } ) ) Fn ℋ )
33 eqfnfv ( ( ( 𝐴 ketbra 𝐴 ) Fn ℋ ∧ ( proj ‘ ( span ‘ { 𝐴 } ) ) Fn ℋ ) → ( ( 𝐴 ketbra 𝐴 ) = ( proj ‘ ( span ‘ { 𝐴 } ) ) ↔ ∀ 𝑥 ∈ ℋ ( ( 𝐴 ketbra 𝐴 ) ‘ 𝑥 ) = ( ( proj ‘ ( span ‘ { 𝐴 } ) ) ‘ 𝑥 ) ) )
34 29 32 33 syl2anc ( 𝐴 ∈ ℋ → ( ( 𝐴 ketbra 𝐴 ) = ( proj ‘ ( span ‘ { 𝐴 } ) ) ↔ ∀ 𝑥 ∈ ℋ ( ( 𝐴 ketbra 𝐴 ) ‘ 𝑥 ) = ( ( proj ‘ ( span ‘ { 𝐴 } ) ) ‘ 𝑥 ) ) )
35 34 adantr ( ( 𝐴 ∈ ℋ ∧ ( norm𝐴 ) = 1 ) → ( ( 𝐴 ketbra 𝐴 ) = ( proj ‘ ( span ‘ { 𝐴 } ) ) ↔ ∀ 𝑥 ∈ ℋ ( ( 𝐴 ketbra 𝐴 ) ‘ 𝑥 ) = ( ( proj ‘ ( span ‘ { 𝐴 } ) ) ‘ 𝑥 ) ) )
36 26 35 mpbird ( ( 𝐴 ∈ ℋ ∧ ( norm𝐴 ) = 1 ) → ( 𝐴 ketbra 𝐴 ) = ( proj ‘ ( span ‘ { 𝐴 } ) ) )