[Depfis] COLOQUIO DF-FCEyN-UBA 18/12/03

[Diego Harari]

                      COLOQUIOS

         DEPARTAMENTO DE FISICA J.J. GIAMBIAGI
       FACULTAD DE CIENCIAS EXACTAS Y NATURALES
              UNIVERSIDAD DE BUENOS AIRES
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      QUANTUM FEEDBACK CONTROL OF ATOMIC MOTION
                     IN CAVITY QED
 
                     Daniel Steck
             Los Alamos National Lab., USA   
   
            Jueves 18 de diciembre, 14 hs
                Aula Pedro Federman
      1er Piso - Pab. 1 - Ciudad Universitaria

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We consider the problem of controlling via continuous feedback the motion 
of an atom trapped in an optical cavity.  A major challenge in the 
experimental implementation of such a feedback scheme is that one must be 
able to estimate the atomic state in real time.  While the stochastic 
master equation, which incorporates the measurement record, achieves this 
in principle, the real-time integration of this equation is unfeasible on 
the short time scales in this system.  We derive an approximate estimation 
equation for this purpose and design a feedback algorithm to cool the 
atomic motion.  We analyze the performance of this setup analytically and 
through numerical simulations.  We show that this system is remarkably 
robust to parameter variations and that using an additional coherent step, 
cooling to the vibrational ground state should be achievable with high 
probability.  We also analyze the feasibility of implementing this 
algorithm given the speed limitations of current computer hardware
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-- 
Diego Harari  Departamento de Fisica,FCEyN - Universidad de Buenos Aires
               Ciudad Universitaria, Pab.1 - 1428 Buenos Aires, Argentina
Email: harari en df.uba.ar              Phone: (54-11) 4576 3390/7 Ext. 823
Internet: http://www.df.uba.ar/~harari                    Fax: 4576 3357