High-temperature superconductivity has transformed the landscape of solid state science, leading to the discovery of new classes of materials, states of matter, and concepts. However, despite being over a quarter of a century since its discovery, there is still no single accepted theory to explain its origin. This book presents one approach, the strong-coupling or bipolaron theory, which proposes that high-temperature superconductivity originates from competing Coulomb and electron-phonon interactions. The author provides a thorough overview of the theory, describing numerous experimental observations, and giving detailed mathematical derivations of key theoretical findings at an accessible level. Applications of the theory to existing high-temperature superconductors are discussed, as well as possibilities of liquid superconductors and higher critical temperatures. Alternative theories are also examined to provide a balanced and informative perspective. This monograph will appeal to advanced researchers and academics in the fields of condensed matter physics and quantum-field theories.

This book first introduces a single polaron and describes recent achievements in analytical and numerical studies of polaron properties in different e-ph models. It then describes multi-polaron physics as well as many key physical properties of high-temperature superconductors, colossal magnetoresistance oxides, conducting polymers and molecular nanowires, which were understood with polarons and bipolarons.

While basic features of polarons were well recognized a long time ago and have been described in a number of review papers and textbooks, interest in the role of electron-phonon interactions and polaron dynamics in di?- ent materials has recently gone through a vigorous revival. Electron-phonon interactions have been shown to be relevant in many inorganic and organic semiconductors and polymers, colossal magnetoresistance oxides, and tra- port through nanowires and quantum dots also often depends on vibronic displacements of ions. These interactions presumably play a role in hi- temperature superconductors as well. The continued interest in polarons extends beyond the physical description of advanced materials. The ?eld has been a testing ground for analytical, semi-analytical, and numerical techniques, such as path integrals, strong-coupling perturbation expansion, advanced variational methods, exact diagonalization, Quantum Monte Carlo, and other techniques. This book reviews some recent developments in the ?eld of polarons, starting with the basics and covering a number of active directions of research. Single- and multipolaron theories have o?ered more insight into colossal magnetoresistance and in a broad spectrum of ph- ical properties of structures with reduced dimension and dimensionality such as transport, optical absorption, Raman scattering, photoluminescence, magneto-optics, etc. While nobody - at present - has a ?nal theory of hi- temperature superconductivity, we discuss one alternative (polaronic) route. We have bene?ted from discussions with many experts in the ?eld.

While basic features of polarons were well recognized a long time ago and have been described in a number of review papers and textbooks, interest in the role of electron-phonon interactions and polaron dynamics in di?- ent materials has recently gone through a vigorous revival. Electron-phonon interactions have been shown to be relevant in many inorganic and organic semiconductors and polymers, colossal magnetoresistance oxides, and tra- port through nanowires and quantum dots also often depends on vibronic displacements of ions. These interactions presumably play a role in hi- temperature superconductors as well. The continued interest in polarons extends beyond the physical description of advanced materials. The ?eld has been a testing ground for analytical, semi-analytical, and numerical techniques, such as path integrals, strong-coupling perturbation expansion, advanced variational methods, exact diagonalization, Quantum Monte Carlo, and other techniques. This book reviews some recent developments in the ?eld of polarons, starting with the basics and covering a number of active directions of research. Single- and multipolaron theories have o?ered more insight into colossal magnetoresistance and in a broad spectrum of ph- ical properties of structures with reduced dimension and dimensionality such as transport, optical absorption, Raman scattering, photoluminescence, magneto-optics, etc. While nobody - at present - has a ?nal theory of hi- temperature superconductivity, we discuss one alternative (polaronic) route. We have bene?ted from discussions with many experts in the ?eld.

There is a growing understanding that the progress of the conventional silicon technology will reach its physical, engineering and economic limits in near future. This fact, however, does not mean that progress in computing will slow down. What will take us beyond the silicon era are new nano-technologies that are being pursued in university and corporate laboratories around the world. In particular, molecular switching devices and systems that will self-assemble through molecular recognition are being designed and studied. Many labora tories are now testing new types of these and other reversible switches, as well as fabricating nanowires needed to connect circuit elements together. But there are still significant opportunities and demand for invention and discovery be fore nanoelectronics will become a reality. The actual mechanisms of transport through molecular quantum dots and nanowires are of the highest current ex perimental and theoretical interest. In particular, there is growing evidence that both electron-vibron interactions and electron-electron correlations are impor tant. Further progress requires worldwide efforts of trans-disciplinary teams of physicists, quantum chemists, material and computer scientists, and engineers."

There is a growing understanding that the progress of the conventional silicon technology will reach its physical, engineering and economic limits in near future. This fact, however, does not mean that progress in computing will slow down. What will take us beyond the silicon era are new nano-technologies that are being pursued in university and corporate laboratories around the world. In particular, molecular switching devices and systems that will self-assemble through molecular recognition are being designed and studied. Many labora tories are now testing new types of these and other reversible switches, as well as fabricating nanowires needed to connect circuit elements together. But there are still significant opportunities and demand for invention and discovery be fore nanoelectronics will become a reality. The actual mechanisms of transport through molecular quantum dots and nanowires are of the highest current ex perimental and theoretical interest. In particular, there is growing evidence that both electron-vibron interactions and electron-electron correlations are impor tant. Further progress requires worldwide efforts of trans-disciplinary teams of physicists, quantum chemists, material and computer scientists, and engineers."