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In-Depth Information
Table 10.1 The four
functions of a single binary
variable
x i
g 0
g 1
g 2
g 3
0
0
0
1
1
1
0
1
0
1
Table 10.2 Procedure to
identify constant and
nonconstant functions
x i
g 2
Prepared list
Tagged list
Assumed list structure
011
1
¼a 1
101
1
¼a 2
2
2
2
b 1 ¼ð
1
η
Þ
p
þðη
Þð
q
Þ¼
1
2
η
¼
0
:
(10.5)
2
2
b 2 ¼ð
1
η
Þ
p
ðη
Þð
q
Þ¼
1
:
(10.6)
2
[0 1] 0 which after sampling is 1 or true,
determinedwith certaintywith one sampling (or measurement). So a systemcan know
that the original vector is
1] 0 transforms to 1
Since
η
¼
0.5,
η
[1
¼
1) 0 without having to probe and perhaps disturb the
multivibrator. This transform is reversible. For example, [0 1] 0 may be transformed
to be [pq] 0 where p
η
(1
¼
0; q
¼
1/
η
, returning the vector to b
¼ η
[1
1] 0 .
Binary Function Classification Involving One Simulated Qubit
Assuming an ordinary binary function of a single bit, possibilities are, the function
is constant: either g(x i )
¼
0org(x i )
¼
1 for i
¼
1, 2; (note that x 1 ¼
0, x 2 ¼
1)
x i 0 , the complement of x i .
This information is presented in a truth table, Table 10.1 .
Two functions, g 0 and g 3 , are constant functions as x i varies; the other two, g 1
and g 2 , are nonconstant.
Recall that simulated qubits have at their core a set of multivibrator waveforms
operating at a certain frequency and phase. A multivibrator function is a sequence
of rotations, polar and azimuthally, of the probability vector that introduces nega-
tive signs into the presampled output possibilities. For example, two simulated
qubits [a 1 a 2 ] 0 ,[b 1 b 2 ] 0 may be prepared to be [1 1] 0 ,[11] 0 meaning that each has
50 % probability of being true and 50 % probability of being false. Overall there are
finite probabilities for the following combinations a 1 b 1 , a 1 b 2 , a 2 b 1 , a 2 b 2 .
A multivibrator function is defined to be one that places a negative sign on one
more of these terms.
Generalizing, for any number of simulated qubits, the locations of the negative
signs are congruent to the 1s of a particular Boolean function. Negative signs are
invisible in the readout method, so with simple sampling fails to identify the
multivibrator function should it be unknown. A special procedure is required to
identify or at least classify the function. For example, refer to the inverter function,
g 2 , in Table 10.2 .
otherwise it is nonconstant: either g(x i )
¼
x i or g(x i )
¼
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