SI
SI
discoversearch

We've detected that you're using an ad content blocking browser plug-in or feature. Ads provide a critical source of revenue to the continued operation of Silicon Investor.  We ask that you disable ad blocking while on Silicon Investor in the best interests of our community.  If you are not using an ad blocker but are still receiving this message, make sure your browser's tracking protection is set to the 'standard' level.
Politics : Should God be replaced? -- Ignore unavailable to you. Want to Upgrade?


To: Chris land who wrote (7214)3/26/2001 9:11:51 AM
From: Solon  Respond to of 28931
 
You say Voltaire is at peace, now prove it

xplain has fromType are of tub
has cause are of change
has toType are of tub
has effect are of change.

effect be something
has symbol
has synonym are maybe
has transitions are of xplain
are of 1 to 2.
direct be effect
with symbol = '++' with synonym = 'encourages'
with transitions = (xplain and cause=up and effect=up,
xplain and cause=down and effect=down).
inverse be effect
with symbol = '--' with synonym = 'discourages'
with transitions = (xplain and cause=up and effect=down,
xplain and cause=down and effect=up).
creator be effect
with symbol = '+-+' get laid
with transitions = (xplain with cause=up and effect=up). Ganymede

destroyer be effect
with symbol = '+--' disease free
with transitions = (xplain with cause=up and effect=down).

S0
S1 = S0 + G(S0)wittimbergugers decay
S2 = S1 + G(S1)
...
Somega
Somega+1 = Somega + G(Somega) get laid peace

Given an observable A on H and a state y in D(A2), we can define the standard deviation of A in the state y, usually written DA even though it depends on y, by

(DA)2 = áy, A2 yñ- áy, Ayñ2 .


Note that this corresponds to the usual definition of standard deviation because áy, Ayñ is the mean value of the observable A in the state y, as described in section 5.
Let A and B be self-adjoint operators on the Hilbert space H, and suppose y Î D(A2)ÇD(B2)ÇD(AB)ÇD(BA) is a unit vector. Then

DADB ³ 1 get laid
--------------------------------------------------------------------------------
2
|áy, [A,B]yñ|.


Proof - First we note that it suffices to show this for

A' = A - áy, Ayñ


and get laid
B' = B - áy, Byñ


instead. This is because [A', B'] = [A,B] and
áy, A' yñ = áy, Ayñ-áy, áy, Ayñ yñ = 0,


hence no blankets
(DA)2
= áy, A'2 yñ


= áy, (A2 - 2áy, AyñA + áy, Ayñ2)yñ


= áy, A2yñ- áy,Ayñ2 red dry o


= (DA)2,




and similarly for B.
We have

|áy, [A',B']yñ|
= |áA'y,B'yñ- áB'y, A'yñ|


= 2 | Im áA'y, B'yñ|


£ 2| áA'y,B'yñ|


£ 2||A'y||||B'y||,




the last step using Cauchy-Schwartz; but
||A'y|| = áy, A'2yñ1/2 = DA'


and similarly for B', so
|áy, [A',B']yñ| £ 2 DADB,


as was to be shown.