Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Power of photonic states: from quantum computation to cosmology   This thesis is an exploration of the power of photonic resources, as viewed
from several different but related perspectives. They range from quantum
computation, precision parameter estimation to the thermodynamics of
relativistic quantum systems, as applied to cosmology in particular.
  In chapter 1, we propose a new quantum computational model, called the `power
of one qumode', that relies mainly on a single-mode photonic squeezed state. In
particular, we show the amount of squeezing can quantitatively relate the
resource requirements of factoring to the problem of finding the trace of large
unitary matrices, a result with consequences for understanding how powerful
quantum computation really is. Furthermore, we can connect squeezing to other
known resources like precision, energy, qudit dimensionality and qubit number,
which is a useful stepping stone to finding the resources that enable quantum
computation.
  In chapter 2, we exploit the quantum mechanical properties of photonic states
for use in precision parameter estimation of general linear optical processes,
which is useful for a diverse number of applications, from characterising an
unknown process in a photonic quantum computer to biological imaging. We
introduce a formalism that quantifies this improvement in precision. We also
provide conditions under which one can easily check for photonic states that
are optimal to use in this context, which is a potentially important result for
future experimental efforts.
  In chapter 3, we explore the connection between two-mode squeezed states,
commonly used in quantum optics, and relativistic quantum processes, in
particular in cosmology. Using this connection, we apply recently developed
tools from the thermodynamics of quantum systems perturbed far from equilibrium
to address an old question of entropy production in cosmology from a surprising
new angle.

12
The categories of this paper are: nucl-th
17
The categories of this paper are: q-fin
4
The categories of this paper are: cond-mat
10
The categories of this paper are: q-bio
30
The categories of this paper are: q-alg
20
The categories of this paper are: acc-phys
25
The categories of this paper are: patt-sol
31
The categories of this paper are: ao-sci
26
The categories of this paper are: bayes-an
6
The categories of this paper are: astro-ph
22
The categories of this paper are: chao-dyn
35
The categories of this paper are: mtrl-th
11
The categories of this paper are: hep-lat
32
The categories of this paper are: atom-ph
0
The categories of this paper are: hep-ph
16
The categories of this paper are: stat