their work discrete body those and negative temperatures state
has been done by stay final you being e
a bad performance of the narrow band two d v
don't work well but
and then tanya quality
in a collaboration among the universities of lawrence unitary state off glide in aberdeen in
the united kingdom
and the c in a incest of your in q no unique id
first of all we want to clarify the meaning of negative temperatures
by considering an is somewhat of to level up tones
where the total internal energy is bound
in the middle energy state all the atoms are in the ground state
since this state is perfectly or that it's entropy zero
but so is the entropy for the maximum energy state
well all the atoms and in the excited state
this means that if we plot of the entropy s as a function of the
internal energy you we obtain a curve with at least one maximum value
since the temperature t is the inverse of the slope of these curve we observe
on the left side of the pitch or positive slope corresponding proposed a temperature
and the maximum f zero slope when we have you think temperature
and on the right of the pitch or negative slopes and negative temperatures
this means the negative temperatures at extremely hot
and the ball the temperature point
this does not in anyway violated the absolute zero temperature is sorta
i introduced by a lot caving
in this paper we study negative temperatures states
in the discrete can only enough shutting in equation
this equation describes accurately both i think on the state you need the optical at
these but also racial couple optical waveguide
they helping to describe i the tunnelling effect of the b c in the optical
at this or the coupling among the wave guides
it is important to note that in the discrete can only initiating an equation
that out to course of quantities the total energy and the total atomic density
it is possible to provide a statistical mechanics description
all the solutions of the discrete only the shouldn't get equation
as displayed in this diagram would we report to the energy density verse of the
part versus the particle density
there exist a line of you think temperature unified
separating a region of negative temperatures from a legion at positive temperatures
the main question addressed in our work ease
can we access the region at negative temperatures
on that i we see the temporal evolution of two different realizations involved a pretty
temperature line
in both cases we observe the formation and then take elation
of discrete body this that a highly spatially localized states corresponding to large values of
the particle density in just if you laugh decides
by increasing the size of the lack this aim we also observe that the density
of body there's approaches require the stationary value corresponding to any terribly the distance of
around nine hundred lap decides
the presence of many discrete body thus in the quasi-stationary state and negative temperature is
displayed in this animation
there being the this the role approaches the final value that is independent of the
initial condition and so that as the inverse of the temperature be to
that converges the was negative values measured by suitable michael canonical thermometer
it is possible in the discrete non linear fitting in equation to move from positive
to negative temperatures
without of the features changes of the sign of the energy
by following a method introduced by some of us in two thousand and seeks one
can remove particle and energy of the boundaries of the last is
in progressively more across the line of v thingy temperatures
in conclusion we have demonstrated
the negative temperatures states with discrete readers should be experimentally realizable in b c in
optical laugh theses and large arrays of optical waveguide
it is possible to move from positive to negative temperatures but if the expansion of
the b c
on a large overlap this or by removing particles and energy from the boundary
these methods do not rely on artificial changes of the sign of the total energy
simply marloes