6.3 Benefits and Applications
197
f BE
(E - µ) / k T
B
1
0
2
3
-1
Occupation function
0
1
2
3
4
f MB
f FD(T>0)
f FD(T=0)
Fig. 6.3 Maxwell–Boltzmann (MB), Fermi–Dirac (FD) and Bose–Einstein (BE) distribution functions, representing the occupation functions for classical particles, fermions and bosons, respectively. They are plotted on a common scale vs. (E − μ)/k B T , that is with respect to the chemical
potential μ as the reference energy. Drawn freely after [2], with the FD distribution at absolute zero
added for comparison with the high-temperature behaviour
However, the particle density in the Bose cloud must be dilute enough so that threeparticle interaction effects, which could lead to the formation of a solid instead of a
BEC, can be neglected.
The condensation phenomenon, which is practically achievable at elevated temperatures for bosonic exciton–polaritons in optical microcavities, was in the past
two decades exploited to demonstrate a novel type of coherent light source, labelled
polariton laser. An overview on this subject is provided for instance in [15, 38,
39], with theoretical considerations provided e.g. in [40–42]. Numerous studies
on optically-pumped polariton systems were performed to better understand the
condensation behaviour for cavity–polaritons, their phase-transition criteria and the
coherence signatures for such driven–dissipative condensates (cf. [43–46]), involving works with external fields. Nowadays, Bose fluids in solids are further studied
with respect to utilisation in novel device concepts for optical circuitry and quantum information processing applications, as outlined in [47], and the utilisation of
coherent polariton lasers is at the verge [48, 49].
Quantum structures such as photonic quantum boxes with their discrete energies
are known to affect the condensation properties, for instance by sufficient decoupling
of the condensate from uncondensed particles in the system, i.e. by reduced groundstate–reservoir interactions (as discussed in [50]). Also, quantum structures with
strong confinement and thereby increased oscillator strength play an important role
for light–matter interactions. In this context, semiconducting 2D materials
9 with
9 The class of 2D materials is often also referred to as quantum materials.
197
f BE
(E - µ) / k T
B
1
0
2
3
-1
Occupation function
0
1
2
3
4
f MB
f FD(T>0)
f FD(T=0)
Fig. 6.3 Maxwell–Boltzmann (MB), Fermi–Dirac (FD) and Bose–Einstein (BE) distribution functions, representing the occupation functions for classical particles, fermions and bosons, respectively. They are plotted on a common scale vs. (E − μ)/k B T , that is with respect to the chemical
potential μ as the reference energy. Drawn freely after [2], with the FD distribution at absolute zero
added for comparison with the high-temperature behaviour
However, the particle density in the Bose cloud must be dilute enough so that threeparticle interaction effects, which could lead to the formation of a solid instead of a
BEC, can be neglected.
The condensation phenomenon, which is practically achievable at elevated temperatures for bosonic exciton–polaritons in optical microcavities, was in the past
two decades exploited to demonstrate a novel type of coherent light source, labelled
polariton laser. An overview on this subject is provided for instance in [15, 38,
39], with theoretical considerations provided e.g. in [40–42]. Numerous studies
on optically-pumped polariton systems were performed to better understand the
condensation behaviour for cavity–polaritons, their phase-transition criteria and the
coherence signatures for such driven–dissipative condensates (cf. [43–46]), involving works with external fields. Nowadays, Bose fluids in solids are further studied
with respect to utilisation in novel device concepts for optical circuitry and quantum information processing applications, as outlined in [47], and the utilisation of
coherent polariton lasers is at the verge [48, 49].
Quantum structures such as photonic quantum boxes with their discrete energies
are known to affect the condensation properties, for instance by sufficient decoupling
of the condensate from uncondensed particles in the system, i.e. by reduced groundstate–reservoir interactions (as discussed in [50]). Also, quantum structures with
strong confinement and thereby increased oscillator strength play an important role
for light–matter interactions. In this context, semiconducting 2D materials
9 with
9 The class of 2D materials is often also referred to as quantum materials.