Saturday, November 15, 2014

Solutions to EPR-Nonlocality Problems

1) From the quantities given:

dt/ t » GM(1/r1 - 1/r2) » g(dr)/ c2

where G is the Newtonian gravitational constant, M is the Earth's mass, and g is the acceleration of gravity (g = 980 cm/ sec2 in cgs) and c = 3 x 1010 cm/sec.

From the hypothetical data given in the post, the box deflection (r2 - r1)was 0.001 mm = 0.0001cm, then:

dt/t ~ (980 cm/s2)(10-4 cm)/ (3 x 1010 cm/sec )2

dt/t
»  10-22

and for an interval say t = 0.01 sec, dt =

(10-22 )(0.01 sec) = 10-24 sec

This observation would actually generate a time uncertainty of 10-24  sec- and hence an uncertainty
DE in the energy of the photon.,

The mass uncertainty is D m = DE/ c2

DE Dt  >  h/ 2p    so DE »  1.054 x 10 -34 J-s/ 10-24  s

DE »    1.054  x  10 -10 J

Therefore: D m = DE/ c2 »    1.054  x  10 -10 J/ 3 x 108 ms-1

D m »  3.5 x  x  10 -17 kg

And the uncertainty in weight is:

D W »  D m  g »  3.5 x  x  10 -17 kg (9.81 N/ kg)

Or:  D W »    1.2 x  10 -17 N


2) The experimental result:

S = (A1,A2)I + (A1,A2)II + (A1,A2,)III + (A1,A2)IV =

2.65 + 0.10

is at the cusp of necessary threshold (2.70) for basic confirmation. However, the uncertainty (+ 0.10) suggests that at least some of the results might be confirmed but this would have to be subject to careful re-test.


3) We have a theoretical  wavelength, l = 2p / Dk, where Dk is the expected width of the wave packet.  If Dk = 0.5 nm, and x = 1 nm with xo = 0.5 nm, and we are to compute the E-field amplitude:  Ez    

Solution:  We know

Dk = p / x = p / (0.5  nm) = 2p  nm, but 2p (nm) > 2 nm.

The maximum of the wave packet is approximated closely by the square of the amplitude:

[ Ez ] 2 =    4 sin2 2p (1 – 0.5) / (1 – 0.5) =

  4 sin2 2p


But:  sin  2p = 0   so [ Ez ] 2 =   0

Physical interpretation: 

The dimension of Dk relative to   Dx =  (x  -  xo )

Implies no wave packet can exist.

4) In a particular experiment to test Bohmian quantum mechanics on a computer, the uncertainty in one input turns out to be: Dt  =   10 -39 s  and in the other,  Dfk  = 10 -51 m. From this data, find the quantity b. Then compose a form of the Uncertainty principle and obtain the product ab. (Where ab plays the same role as  ħ in the conventional form of the Uncertainty principle.) Comment on how your product ab compares to ħ.


Solution:

(d  Dfk) 2  = b (Dt)

(d  Dfk)   = b 1/2   (Dt)1/2 

b=    (d  Dfk) 2   /  (Dt) =  (10 -51 m) 2 / (10 -39 s ) =

  (10 -63 m) 2 / s


(Note: a is a constant of proportionality so let a = 1)

Bohm notes that p k   also fluctuates at random over the given range so:

d p k =  a b 1/2 /   (Dt)1/2   =  

(10 -51 m) 1/2  / (10 -39 s ) 1/2    =   10 -6 m1/2  s -1/2  


Combining all the preceding results one finally gets a relation reflective of the Heisenberg principle, but time independent:

d p k   (d  Dfk  ) = ab  =    (10 -6 m1/2  s -1/2  )( 10 -51 m) 

=   (10 -57 m 3/2   s -1/2 ) 


This is analogous to Heisenberg’s principle, cf.

dp dq  <  ħ    except that the units of ħ are J-s.


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