An international group of researchers has discovered a surprisingly straightforward connection between the rates of energy and information transfer across an interface that links two quantum field theories. This research was published in Physical Review Letters on August 30.
The concept of an interface between different quantum field theories is crucial and appears in various contexts within particle physics and condensed matter physics. However, determining the rates at which energy and information are transmitted through these interfaces has been quite challenging.
Hiroshi Ooguri, a professor at the Kavli Institute for the Physics and Mathematics of the Universe (Kavli IPMU, WPI) at the University of Tokyo, along with his colleagues, Associate Professor Yuya Kusuki from Kyushu University, and Professor Andreas Karch alongside graduate students Hao-Yu Sun and Mianqi Wang from the University of Texas at Austin, have demonstrated that for two-dimensional theories exhibiting scale invariance, there exists a set of simple and universal inequalities linking three key aspects: the rate of energy transfer, the rate of information transfer, and the dimensionality of Hilbert space (defined by the rate of increase of states at high energy). Specifically, the relationship can be expressed as follows:
[ energy transmittance ] ≤ [ information transmittance ] ≤ [ size of the Hilbert space ].
This means that to convey energy, there must also be a transfer of information, and both processes necessitate a sufficient number of states. Furthermore, they found that no stronger inequalities could be established.
While energy and information transfer are critical elements of study, calculating them has proven difficult, and no prior relationships between them were identified. By highlighting the inequalities among these factors, this paper offers fresh insights into this significant yet challenging aspect of physics.
