Magnetic dipole-dipole interaction induced by the electromagnetic field

Abstract

We give a derivation for the indirect interaction between two magnetic dipoles induced by the quantized electromagnetic field. It turns out that the interaction between permanent dipoles directly returns to the classical form; the interaction between transition dipoles does not directly return to the classical result, yet returns in the short-distance limit. In a finite volume, the field modes are highly discrete, and both the permanent and transition dipole-dipole interactions are changed. For transition dipoles, the changing mechanism is similar with the Purcell effect, since only a few number of nearly resonant modes take effect in the interaction mediation; for permanent dipoles, the correction comes from the boundary effect: if the dipoles are placed close to the boundary, the influence is strong, otherwise, their interaction does not change too much from the free space case.Comment: 8 pages, 2 figure

Single photon pulse induced transient entanglement force

“…With the help of our defined force operator, we explicitly show that the resonant dipole-dipole interaction (RDDI) force fundamentally arises from two-body entanglement, which is significantly different from the van der Waals force. Our theoretical framework combines quantum theories of single-photon pulse scattering [17][18][19][20] and the macroscopic quantum electrodynamics approach of dipoledipole interaction [21][22][23][24]. We thus show that the quantum statistics of the incident (Fock-state versus coherent-state) pulses lead to significant differences in the induced RDDI entanglement forces.…”

“…After absorption of a single photon pulse, the RDDI force dominates with a greatly enhanced amplitude ∼10 −22 N. This force can be further enhanced upto 10 −19 N with surface plasmons-plaritons. Using phase-coherent Doppler velocimetry, force sensitivity of~-10 N Hz 24 can be approached in trapped ion systems [32]. In a Mach-Zehnder-type interferometer with a free fall cesium atom from an optical tweezer, a force of magnitude 3.2×10 −27 N has been measured in an experiment [33].…”

“…can also be obtained with Heisenberg equations [24] 3 . This master equation can also be found in [22,35,39].…”

The Correlation Production in Thermodynamics

“…The baths, due to their large size, are usually considered as unaffected by the system, and only provides a background with fluctuations. But the system surely has influence to its environment [ 16 , 23 , 35 ]. For example, when the system emits energy, this energy is indeed added to the environment.…”

“…For a confined area with periodic boundary condition , the solution can be constructed with the help of the above free space one, i.e., Here can be regarded as the periodic “image” solution in the interval ( Figure 4 a) [ 35 ]. Clearly, Equation ( 33 ) satisfies the periodic boundary condition, as well as the initial condition ( 30 ), and it is simple to verify each summation term satisfies the above Liouville Equation ( 29 ), thus Equation ( 33 ) describes the full microstate PDF evolution in the confined area with periodic boundary condition.…”