Research On Quantum Heat Engines Based On Electromagnetically Induced Transparency

Electromagnetically induced transparency is a very interesting phenomenon in the field of quantum optics.It is caused by atomic coherence and quantum interference in the interaction between multi-level atoms and coherent light fields.It brought a lot of valuable applications,such as the reduction of light group velocity,reversible light storage,non-linear enhancement and so on.People have been studying its potential value.In recent years,the quantum heat engine has also developed and improved in many applications,even under some special conditions,it can overcome the limition value of the Carnot heat engine.The quantum heat engine can be greatly adjusted by quantum coherence.Therefore,some people have combined quantum heat engines with electromagnetically and used EIT to construct a non-traditional ideal quantum heat engine likely.We have deeply researched and studied it.On the basis of the previous research work,we have improved the work of the predecessor.We propose two schemes in this dissertation:on the basis of the original Harris'work,the first scheme is to improve and increase the output brightness by adding a microwave field between two low energy levels.The second scheme is to consider how to realize the quantum heat engine in inhomogeneously broadened solid state medium,we has found that it is not all materials are suitable for quantum heat engines.In the first scheme,we present an improved version of such a heat engine by adding a microwave field in the ?-type atomic system to modify the cross sections for absorption and emission.We find that this microwave-assisted atomic system behaves as a heat engine only when(?)all three laser or microwave fields resonate with their corresponding transitions and(?)the relative phase between these fields is n? with(n=0,±1,±2,……).In particular,below the threshold of lasing without inversion,the engine's output field exhibits a brightness increasing with the microwave's intensity,and the brightness in the presence of a weak microwave field can be tens of(or even larger)that in the absence of a microwave field.We also note that the microwave field has the equivalent effect of increasing(decreasing)the hot(cold)reservoir's temperature.In the second scheme,we theoretically discuss how the quantum heat engines realized in inhomogeneously broadened solid media.The main distinction of solid media is that the solid media produces inhomogeneous broadening of their optical and spin transitions.We have mathematically verified a method of substitution,that is,the polarization of inhomogeneously broadened solid media can be obtained by integrating the polarization of homogeneously broadened gaseous media,in which there is a relatively simple method of substitution.We also give a conditional expression that is to judge whether the material can achieve the quantum heat engines.We select two different materials for discussion.We observe that eligible materials can produce narrow and bright brightness at the center of the line.