Fundamental Research Of Quantum Measurement&Weak Measurement And Its Application In The Detection Of Gravitational Wave

The most exciting and important scientific event in the beginning of year 2016 undoubtedly should be the direct observation of gravitational waves by advanced Laser Interferometer Gravitational-Wave Observatory(LIGO).The detec-tion of ultra-small gravitational waves by high sensitivity LIGO implies the new era of gravitational-wave astrophysics.The sensitivity of the gravitational-wave detectors can be further improved with the latest state-of-art technologies and the possible global gravitational-wave network joined by Advanced VIRGO,the KAGRA interferometer and the planned third LIGO in india will tremendously enhances parameter estimation and sky location.The LIGO detector is essentially a modified Michelson interferometer,in which phase difference between its two orthogonal arms caused by gravitational-wave strain is measured.Except for using significant development technology and new facilities to dramatically improve the sensitivity of gravitational-wave detectors,it is interesting and important to ask whether or not there exists possible types of gravitational-wave detectors wit high sensitivity other than the type of Michelson interferometer,which operates based on different theory of measurement.The recent progress in the theory of quantum measurement e.g.,weak measurements may offer positive answer.Weak measure-ment,which was proposed by Aharonov,Albert and Vaidman,focus on disturbing system as small as possible so that the state of a system would not collapse after measurement and a projective measurement is subsequently performed for realizing post-selection of the state of the system.Weak measurement has been shown powerful in solving paradox,reconstructing quantum state,and especially amplifying ultra-small signal.In this thesis,we propose a universal protocol to realizing ultra-small phase signal in the framework of weak measurement and provide specific optical configuration.Based on this progress,by introducing optical cavities,we propose and design a new-type laser interferometer gravitational-wave detector based on weak measurement amplification,which we call it WMAGO.The detail calculations of quantum noise spectrum show that WMAGO owns lower quantum noise in higher frequency compared with LIGO,which implies that WMAGO has higher strain sensitivity in higher frequency and broader bandwidth.The several results in this thesis including:1:Based on the physical fact that only eigenstates and its corresponding prob-abilities of observable are actually measured,we propose that observable should be reformulated as Normal operator rather than Hermitian operator.2:By using weak measurement,we experimentally first observe the double Bell inequality violations among multiple observers with one entangled photonic pair.3:We demonstrate the first quantum adder in photonic system,which is capable of superposing arbitrary two photonic qubit given that they have non-overlap with the reference state.4:We propose the realization of sequential measurements of arbitrary observables and experimentally demonstrate for the first time the measurement of sequential weak values of three non-commuting Pauli observables by using genuine single photons.5:we propose a universal protocol to realizing ultra-small phase signal in the framework of weak measurement and provide specific optical configuration.Based on this progress,by introducing optical cavities,we propose and design a new-type laser interferometer gravitational-wave detector based on weak measurement amplification WMAGO.The detail calculations of quantum noise spectrum show that WMAGO owns lower quantum noise in higher frequency compared with LIGO,which implies that WMAGO has higher strain sensitivity in higher frequency and broader bandwidth.6:Regarding quantum state amplification as quantum state transformation,we show that deterministic noiseless amplification of coherent states chosen from a proper set is physically attainable.