8 27.1 The Heisenberg uncertainty principles The quantum mechanical vacuum is a seething sea of particle-antiparticle pairs, called virtual particles, since their existence is ephemeral The pairs of virtual particles well up out of nothing, live for very short time, and then disappear(annihilate each other) According to energy-time uncertainty principle ∠EAt≥h For a virtual electron-positron pair h h t 4E 2mc 6.626×10 =404×10-2ls 2(9.11×10)(3×103) 8 27. 1 The Heisenberg uncertainty principles C. The verification of experiment: H. B. G. Casimir effect: Lamb shift: Example: Light of wavelength 632.8 nm is incident on an extremely fast shutter that chops the beam into pulses. The shutter stays open for only 1.5x10-9s. what is the approximately minimum range of wavelengths m in the light pulses that pass the shutter9 The quantum mechanical vacuum is a seething sea of particle-antiparticle pairs, called virtual particles, since their existence is ephemeral. The pairs of virtual particles well up out of nothing, live for very short time, and then disappear(annihilate each other). According to energy-time uncertainty principle ∆E∆t ≥ h 4.04 10 s 2(9.11 10 )(3 10 ) 6.626 10 2 21 31 8 2 34 2 − − − = × × × × = = = mc h E h t ∆ ∆ For a virtual electron-positron pair §27.1 The Heisenberg uncertainty principles c. The verification of experiment: H. B. G. Casimir effect: Lamb shift: Example: Light of wavelength 632.8 nm is incident on an extremely fast shutter that chops the beam into pulses. The shutter stays open for only 1.5×10-9 s. What is the approximately minimum range of wavelengths ∆λ in the light pulses that pass the shutter? §27.1 The Heisenberg uncertainty principles