Discussion Overview
The discussion centers on the topic of quantum field theory (QFT) at finite density, specifically at zero temperature. Participants explore the availability of references and resources related to this area, distinguishing it from finite temperature QFT, and address the implications of field excitations in the ground state of interacting theories.
Discussion Character
- Exploratory
- Technical explanation
- Debate/contested
Main Points Raised
- One participant expresses confusion about finding references for QFT at zero temperature and finite density, suggesting that finite temperature resources may not be applicable.
- Another participant notes that QFT at finite temperature is more commonly discussed and is akin to non-relativistic many-body theory, indicating a lack of familiarity with finite density QFT.
- A participant attempts to clarify the concept of interacting QFT at zero temperature, mentioning the presence of field excitations at the ground state, which they acknowledge may seem contradictory.
- One participant asserts that the vacuum state, defined as the ground state, has no excitations, but questions arise about approximating the interacting theory starting from the free theory.
- Another participant discusses finite-temperature/density perturbation theory, emphasizing the correction of both the state and dynamics of fields, and mentions the use of diagrammatic rules.
- A question is raised about the availability of calculations in finite temperature field theory books, particularly those using path integrals.
- A participant shares a manuscript focusing on real-time formalism and provides several textbook references relevant to finite-temperature field theory.
Areas of Agreement / Disagreement
Participants express differing levels of familiarity with QFT at finite density, leading to a lack of consensus on the topic. While some agree on the existence of QFT at zero temperature, the implications and resources related to finite density remain contested.
Contextual Notes
There are unresolved assumptions regarding the definitions of states and excitations in the context of interacting theories versus free theories. The discussion also highlights the potential limitations of existing literature in addressing the specific needs of participants.