Meir–Wingreen formula
The Meir–Wingreen formula or Weir–Wingreen–Jauho formula describes the electric current through an arbitrary mesoscopic system. It was formulated by Yigal Meir and Ned Wingreen,{{cite journal|last=Meir|first=Yigal|author2=Ned S. Wingreen|title=Landauer formula for the current through an interacting electron region|journal=Physical Review Letters|year=1992|volume=68|issue=16|pages=2512–2515|doi=10.1103/PhysRevLett.68.2512|bibcode = 1992PhRvL..68.2512M|pmid=10045416}} and later extended along with Anti-Pekka Jauho.{{Cite journal |last=Jauho |first=Antti-Pekka |date=1994 |title=Time-dependent transport in interacting and noninteracting resonant-tunneling systems |url=https://journals.aps.org/prb/abstract/10.1103/PhysRevB.50.5528 |journal=Physical Review B |volume=50 |issue=8 |pages=5528–5544 |doi=10.1103/PhysRevB.50.5528|pmid=9976896 |arxiv=cond-mat/9404027 }} It describes the current using non-equilibrium Green's functions and Keldysh formalism.{{Cite book |last=Ryndyk |first=Dmitry |url=https://books.google.com/books?id=0BMpCwAAQBAJ&dq=meir-wingreen-jauho&pg=PA216 |title=Theory of Quantum Transport at Nanoscale: An Introduction |date=2015-12-08 |publisher=Springer |isbn=978-3-319-24088-6 |language=en}}
When the interaction between electrons is neglected, this formula reduces to the Landauer formula. This textbook formula{{cite book|last1=Jauho|first1=Hartmut Haug, Antti-Pekka|title=Quantum kinetics in transport and optics of semiconductors|date=2008|publisher=Springer|location=Berlin|isbn=978-3540735618|pages=170|edition=2nd, substantially rev.}} has become a standard tool for calculating the current through various systems, such as molecular junctions, quantum dots and nanoscale devices.
Formula
It reads
where is the elementary charge, are the coupling matrices of the left (L) and right (R) leads, is the Keldysh Green's function, the retarded Green's function, the advanced Green's function, and the Fermi–Dirac distribution of lead b.{{Cite book |last=Kamenev |first=Alex |url=https://books.google.com/books?id=CwlrUepnla4C&q=kamenev+non-equilibrium |title=Field Theory of Non-Equilibrium Systems |date=2011-09-08 |publisher=Cambridge University Press |isbn=978-1-139-50029-6 |language=en}}