[ca] La recerca dels components fonamentals de la natura 'es l'objectiu primordial de la f'ısica de part'ıcules. Des del descobriment de l'̀atom, estructures m'es i m'es fonamentals s'han descobert, les quals componen la mat̀eria. El Model Est̀andar de la f'ısica de part'ıcules assumeix l'exist̀encia d'una s̀erie de part'ıcules considerades fonamentals, incloent el bos'o de Higgs. No obstant, hi ha fortes motivacions per creure que almenys algunes d'aquestes part'ıcules s'on compostes i, de fet, la seva naturalesa es podria revelar a l'LHC. El principal problema de les teories que descriuen part'ıcules compostes 'es el fet de que, en certs regims, els constituents d'aquestes estan fortament acoblats. El tractament de teories fortament acoblades 'es un dels reptes m'es importants en la f'ısica de part'ıcules actual ja que aquest tipus de teories no poden esser tractades en el marc de la Teoria Qùantica de Camps, que 'es l'eina principal en la f'ısica tèorica d'altes energies. L'estudi de models en dimensions extra ha aportat una visi'o m'es profunda d'aquest problema, ja que aquests models es poden entendre com teories 'hologr̀afiques' que exhibeixen una diǹamica d'acoblament fort. El prop̀osit d'aquesta tesis 'es l'estudi de diferents sistemes de part'ıcules compostes. Ens centrem en el desenvolupament de models en dimensions extra que es poden considerar com aǹalegs a sistemes fortament acoblats presents a la natura, aquests s'on la Cromodiǹamica Qùantica y els sistemes superconductors. A m'es tamb'e analitzem el cas de la naturalesa composta dels quarks de manera geǹerica a trav'es de l'estudi dels efectes de models expl'ıcits a energies inferiors a l'escala de nova f'ısica.

[en] The search for compositeness is a paramount goal in particle physics. Since the discovery of the atom, more and more fundamental structures have been discovered in nature from which matter is compound. The Standard Model of particle physics assumes the existence of a set of fundamental particles, including the Higgs boson, that possess no structure. Nevertheless there are strong motivations to believe that at least some of them could be composite and indeed its nature could be unraveled at the LHC. The main difficulty of theories of composite particles is that, in certain regimes, their constituents are strongly coupled. Dealing with strongly coupled theories is a major puzzle in theoretical physics since they can not be understood in the usual framework of Quantum Field Theories, which is the main tool available in theoretical high energy physics. Fortunately, the study of extra dimensional theories has allowed us to gain deeper insights on this issue since these models can be viewed as 'holographic' theories exhibiting strong dynamics. The purpose of this thesis is the study of different composite systems which exhibit strong dynamics. We focus on the development and study of extra dimensional models which can be interpreted as analogs of some strongly interacting systems present in nature, these are Quantum Chromodynamics and superconducting systems. Moreover we also analyze the case of quark compositeness in a model independent way by studying the effects of explicit models at energies below the cut-off scale of New Physics.