Quantum limits and entanglement in metrology and magnetometry - Eugene Polzik

Ultimate sensitivity of metrology and sensing is defined by the fundamental principles of quantum physics. The quantum state of a system determines the magnitude of its quantum fluctuations. The optimal balance between the information about the system obtained during the measurement and the destructive back action of the measurement on the measured object is again defined by the laws of quantum mechanics. I will describe two experiments in which we have explored quantum limits and improvements brought about by entanglement in ultra-sensitive magnetometry with 1012 room temperature atoms and in an atom clock with cold and trapped Caesium atoms.