Many attempts have been made to trace biophoton emission back to coherent
states of the biophoton field [2, 6]. In this paper I would like to add
a further description which is based on the well-known form of a Hamiltonian
that keeps coherent states coherent. By evaluating the properties of coherent
states under the condition of a Hamiltonian that conserves the coherence
of the field, one sees that all the properties of biophoton emission can
be looked upon as necessary consequences. On the other hand, it is unlikely
(if not impossible) to understand the properties of biophoton emission
in terms of chaotic emission. An example of an application of Gurwitsch's
great idea of mitogenetic activity shall demonstrate the value of this
approach.
A coherent state is defined as an eigenstate of the annihilation operator
a, i.e.
. (1)
Glauber and Mehta et al.[7, 8] have shown that a coherent state remains
coherent at all times when the Hamiltonian takes the form
, (2)
where the terms describe the free energy, the exchange of energies among
modes and the interaction of classical currents with the radiation modes.
The functions f and B are real, while g(t) are arbitrary complex functions
of time t. Without loss of general significance, we simplify the summation
by introducing the functions
Thus we write instead of eq.(2)
Let us now calculate the properties of a coherent state |a> under the
influence of the Hamiltonian H(t).
The Schrödinger equation takes the form
. (3)
The initial condition is
The solution can be written as
. (4)
Consequently we obtain
, (5)
where
are abbreviations of
,
respectively.
Since
is simply a C-value, we can factorise:
(6)
where we used the Baker-Hausdorff identity
.
With straight-forward calculation using
we
arrive at
(7)
By use of
where D(a) is the displacement
operator and
the vacuum state, and by use
of the Baker-Hausdorff identity, we obtain
(8)
The last two operators combine again to a displacement operator and
- by use of the Baker-Hausdorff identity - we arrive at
The final solution then takes the form
where
. (10b)
The phase factor
certainly has the norm
1 since
This holds because
and
are real functions.
The number of photons remain unchanged unless
This is a rather remarkable result since it means that as long as no pumping
takes place, sources or sinks of free energy do not influence the photon
number of coherent states. Both free energy and classical currents can
only influence the complex amplitude which moves along circles in the complex
plane. However, as soon as destructive and constructive interference play
a role, the free energy may dramatically change the number of photons of
the coherent field.
Actually, from (10b) we get
(11)
This shows that n(t) is not necessarily constant even if F and G are
not dependent on time. In order to explain this strange result, let us
look at the expectation value of the energy.
(12)
If G = 0, then n(t)=const., and the energy is simply the classical expectation
value
(13)
For
we simply then have
,
which describes the photon energy of a field with a constant number of
photons.
For F = 0 and G = constant, where G and b are real quantities, we have
and (14a)
(14b)
The conservation of energy, i.e. the constant mean value of energy as
well as a constant number of photons, is for G ¹ 0 only possible if
,
which means that an excited coherent state relaxes under ergodic conditions
according to an hyperbolic decay function (as has been already demonstrated
some years ago) [9].
A sufficient condition of a homeostatic regulation of a coherent field
follows from

(15a)
, (15b)
and for
representing again a hyperbolic
law.
It is worthwhile to note that B(t) does not influence the number of
photons in a coherent state, and F also does not change the photon number
unless G is not switched on.
However, we get a remarkable result if one considers the mode coupling
between coherent states of different energy (or frequencies).
Since we can write
, (16)
we can include the non-diagonal elements of
by
the substitution of
(17a)
(17b)
where we used the fact that
is real.
is
the original operator for
and the kth
mode
under study.
Consequently, the mean value n(t) of the photon number
is

(18)
This result points to some rather remarkable features of biological
systems as far as they use the capacity of basic homeostatic regulation
in terms of the
Homeostatic regulation can take place in the following way:
-
, which means that the mean value of creating
and annihilating photons disappears.
a). This may take place, for instance, for destructive interference.
(19)
for all j and k.
n(t) is then constant and independent of free energy as well as of classical
currents. This case is at least partially realised in living matter, since
under stationary conditions n(0) is a constant and the mode coupling satisfies
the f(w)= constant-rule which is just a consequence of (19).
b).
, (20)
where the + accounts for constructive interference. It may take place
immediately when (19) happens. This means that there are regions of destructive
interference and consequently others of constructive interference in such
a way that the total energy is conserved:
, where
is assigned
to destructive interference and
to constructive
interference.
This case corresponds to "photon sucking" which has been already discussed
in former papers [10].
-
One may also consider the case
by oscillatory
behaviour of
in a way that
remains zero by the lack of correlations (for
)
or by the balance of correlations and anticorrelations. However, this case
shall not be discussed here.