Welcome to lonely universe , an infinite realm, each occupied by a single particle!
In this universe, space and time are constructed as follows:
lonely particle
may jump back and forth without any limitations. Let
x
(
⋅
)
denote the position of the particle. Then it is possible for
x
(
t
)
∈
B
i
in one moment and then the particle may suddenly appear elsewhere
x
(
t
′
)
∈
B
j
in the next.
lonely particle
itself experiences a series of ‘eternities’: it experiences each time interval
[
n
t
P
,
(
n
+
1
)
t
P
)
as an infinite series of moments
[
n
t
P
,
(
n
+
1
)
t
P
)
=
⋃
j
≥
0
[
n
t
P
+
t
j
,
(
n
+
1
)
t
P
+
t
j
+
1
)
, where
t
j
=
∑
0
≤
k
<
j
2
−
(
k
+
1
)
t
P
.
For the internal life consciousness of the particle, it perceives each of these finer time intervals as lasting equally long.
Now, one might think that an observer of the universe will only see one particle each time it looks. But that’s not how lonely universe works. The particle radiates each Planck-second a total of E > 0 units of energy. But the location of this radiation depends on how the particle whizzes around. Each time the particle visits a box, it leaves behind a trace. These traces remain linked to each other and the lonely particle divides up the energy amongst them proportional to their frequency of being visited. This means concretely that, for any time point t ∈ [ n t P + t j , n t P + t j + 1 ) , the energy in Box B i is given by E i ( t ) = j + 1 ∣ ∣ ∣ { k ∣ 0 ≤ k ≤ j , x ( n t P + t k ) ∈ B i } ∣ ∣ ∣ ⋅ E . These trace values of energy in the boxes clearly fluctuate in the course of the moments. What the observer finally sees in box B i at time ( n + 1 ) t P is then something between the asymptotic infimum and asymptotic supremum of the trace energy: [ n t P , ( n + 1 ) t P ) ∋ t → ( n + 1 ) t P l i m i n f E i ( t ) ≤ E obs , i ( ( n + 1 ) t P ) ≤ [ n t P , ( n + 1 ) t P ) ∋ t → ( n + 1 ) t P l i m s u p E i ( t ) . So, for example, if x ( t ) ∈ B 1 7 3 at times t ∈ [ n t P + t j , n t P + t j + 1 ) for j = 2 , 5 , 8 , 1 1 , 1 4 , … , then E obs , 1 7 3 ( ( n + 1 ) t P ) ≥ 3 E . Or if x ( t ) ∈ B 4 4 only at times t ∈ [ n t P + t j , n t P + t j + 1 ) for j = 3 ⋅ 1 0 , 3 ⋅ 1 0 0 , 3 ⋅ 1 0 0 0 , … , then E obs , 4 4 ( ( n + 1 ) t P ) = 0 .
Say that the particle lights up the region B i for the observer exactly in case E obs , i ( ( n + 1 ) t P ) . If multiple regions are lit up, the observer may be fooled into thinking that there are particles in all these regions, despite there only being one particle in this universe.
Question:
Is it possible for the particle to move in such a fashion as to light up
all regions
? That is, can the
lonely particle
fool an observer into thinking that the universe is full?
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Of course, this problem has nothing to do with Classical Mechanics - it should be reclassified as Discrete Mathematics or even Calculus.
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that’s what I classified it as originally. Did someone change it?
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I guess somebody must have! Change it back...
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Consider the infinite partition of N given by Π = ( A i ) i ∈ N , where A 0 : = { 0 } ∪ { 2 k + 1 ∣ k ∈ N } and A i = { 2 i ( 2 k + 1 ) ∣ k ∈ N } for i > 0 . One has d ( A i ) = 2 − ( i + 1 ) > 0 for all i ∈ N . Choose the motion of the particle to be such that x ( t ) ∈ B i for all t ∈ ⋃ j ∈ A i [ ( n + 1 ) t P + t j , ( n + 1 ) t P + t j + 1 ) . Then it is easy to see that E obs , i = d ( A i ) E > 0 for all i ∈ N . Thus it is possible for the
lonely particle
to light up all regions.