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Decoherence in strongly coupled quantum oscillators
| Content Provider | Semantic Scholar |
|---|---|
| Author | Ponte, M. A. De Oliveira, Marcos César De Moussa, M. H. Y. |
| Abstract | The process of decoherence of quantum states has long been a central issue in the description of quantum measurements [1–3]. In recent years, experimental advances in the domain of cavity QED and trapped ions have allowed the decoherence of photon [4] and phonon [5] field states to be probed in more depth, providing insights into the borderline between the classical and quantum descriptions of the physical world. The decoherence time of a superposition of coherent states in a cavity field was measured [4] and shown to be in full agreement with theoretical predictions [6,7]. In trapped ions systems, the observed damping of Rabi oscillations has motivated a number of articles on the main sources of noise leading to decoherence [8–11]. Such experimental achievements in matter-field interactions have also encouraged a deep dialog between theoretical and experimental physics, resulting in a degree of mastery of fundamental quantum phenomena that may herald a new stage in the technology of communication [12] and computation [13]. The exploration of the borderline between quantum and classical descriptions of nature [2] has impelled the generation of superposition states of mesoscopic systems, known as “Schrödinger cat states” [4,5]. Such superpositions are irreversibly affected by their surroundings, whose effect is to destroy probability interference (coherence), and continuously transformed into statistical mixtures. Thus, the environment plays a key role in the establishment of a direct correspondence between quantum and classical dynamics. While the decoherence time of a superposition state depends on the amplitude of the field, the relaxation does not, since the model adopted for the relaxation process is amplitude damping, achieved by coupling the systems bilinearly to the degrees of freedom of the reservoir. Decoherence and its dependence upon the amplitude of the superposition state is the main obstacle to the implementation of a logic network based on quantum gates [14,15]. The dream of quantum communication and computation comes up against the nightmare of decoherence mechanisms [16], owing not only to the inevitable action of the surrounding environment but also to the intrinsic fluctuations in the interaction parameters required for logic operations [8–10]. The need for huge superpositions of qubit states in the practical implementation of logical operations imposes the requirements that the quantum systems be totally isolated from the environment and that the interaction parameters involved be tightly controlled. For this reason, investigation of the sources of noise in such promising quantum systems is a crucial step towards the realization of a quantum logic processor. There is also a major effort being made in present-day research, to discover mechanisms to prevent decoherence occurring in actual physical systems, by using parity kicks [17], stroboscopic feedback [18], engineered driving fields [19] or an engineered reservoir [20–22]. In this light, the main concern of the present work is to analyze the coherence dynamics and decoherence process in a network composed of two coupled dissipative oscillators, which may be field modes in dissipative cavities [23], phonon modes of trapped ions [24], phonon modes of surface electrons in liquid helium [25], etc. Master equations are derived for both weakly and strongly interacting oscillators, leading to interesting results concerning the coherence properties of the joint and the reduced system states. This work constitutes a first step towards a more comprehensive treatment of the decoherence process in multipartite quantum systems. |
| File Format | PDF HTM / HTML |
| Alternate Webpage(s) | http://cds.cern.ch/record/641834/files/0309082.pdf |
| Language | English |
| Access Restriction | Open |
| Subject Keyword | Achievement Body cavities Cavity quantum electrodynamics Coherent states Computation (action) Description Dissipative system Electrons Entity Name Part Qualifier - adopted HL7PublishingSubSection |
| Content Type | Text |
| Resource Type | Article |
