Soft-Photons and the entanglement of charged qubtis

Physical qubits from charged particles: IR divergences in quantum information

We consider soft photons effects (IR structure of QED) on the construction of physical qubits. Soft-photons appear when we build charged qubits from the asymptotic states of QED. This construction is necessary in order to include the effect of soft photons on entanglement measures. The nonexistence of free charged particles (due to the long range of QED interactions) lead us to question the sense of the very concept of free charged qubit. In this letter, using the "dressing" formalism, we build physical charged qubits from dressed fields which have the correct asymptotic behavior, are gauge in…

Can a localised quantum system see soft photons?

We ask whether soft photons, defined by asymptotic charges, can have consequences for the outcome of localised quantum processes. We consider a spatially localised two-state system, at rest in flat spacetime, coupled to a $U(1)$ gauge invariant charged scalar field. We find that the system's de-excitation rate does depend on the soft charges that correspond to the radial component of the electric field dressing at the asymptotic infinity; the excitation rate, by contrast, remains zero, regardless of the soft charges. Some implications are discussed.

作为开放量子系统的视界受限主导软量子电动力学

Horizon-Restricted Leading Soft QED as Open Quantum System

研究带电分支码的黑洞视界诱导退相干，通过将其表述为限制在外代数的主导软量子电动力学（作为开放量子系统），推导出相关通道及特性，给出超越双路径可见性的可证伪测试。