TwoPhoton Quantum Entanglement from TypeII Spontaneous Parametric DownConversion
Abstract
The concept of two (or more) particle entanglement lies at the heart of many fascinating questions concerning the foundations of quantum mechanics. The counterintuitive nonlocal behavior of entangled states led Einstein, Podolsky, and Rosen (EPR) to ask their famous 1935 question, "Can quantum mechanical description of reality be considered complete?". Although the debate has been raging on for more than 60 years, there is still no absolutely conclusive answer to this question. For if entangled states exist and can be observed, then accepting quantum mechanics as a complete theory requires a drastic overhaul of one's physical intuition with regards to the common sense notions of locality and reality put forth by EPR. Contained herein are the results of research investigating various nonclassical features of the twophoton entangled states produced in TypeII Spontaneous Parametric Down Conversion (SPDC). Through a series of experiments we have manifest the nonlocal nature of the quantum mechanical "twophoton effective wavefunction" (or Biphoton) realized by certain photoncounting coincidence measurements performed on these states. In particular, we examine a special double entanglement, in which the states are seen to be simultaneously entangled in both spin and spacetime variables. The observed phenomena based on this double entanglement lead to many interesting results which defy classical explanation, but are well described within the framework of quantum mechanics. The implications provide a unique perspective concerning the nature of the photon, and the concept of quantum entanglement.
 Publication:

Ph.D. Thesis
 Pub Date:
 1996
 Bibcode:
 1996PhDT........23P
 Keywords:

 EINSTEIN PODOLSKY ROSEN;
 Physics: General