\begin{tikzpicture}
  % COORDINATES
  \coordinate (O) at (0,0);
  \coordinate (NE) at (12,9);
  \coordinate (SW) at (12,0);
  \coordinate (HF1) at (0,5); % heavy fermion
  \coordinate (AF) at (12,7); % anti-ferromagnetic
  \coordinate (QCP) at (5,0); % quantum critical point
  \coordinate (N1) at (2, 9); % quantum critical
  \coordinate (N2) at (11, 9); % quantum critical
  
  % PATHS
  \def\SG{(HF1) to[out=-20, in=100] (QCP)}
  \def\LG{(QCP) to[out=70,in=210] (AF)}
  \def\QCO{(QCP) to[out=110,in=-60] (N1)}
  \def\QCT{(N2) to[out=-120,in=70] (QCP)}

  % REGIONS
  \fill[blue!9] \SG -- (O) -- cycle;
  \fill[red!9] \LG -- (AF) -- (SW) -- cycle;
  % \fill[yellow!20] \QCO -- \QCT -- cycle;

  \fill[yellow, bottom color=yellow!20, top color=white] \QCO -- \QCT -- cycle;
  
  % LINES
  \draw[thick, dash pattern=on 35pt off 2pt on 2pt off 2pt on 2pt off 2pt on 2pt off 2pt on 2pt off 2pt on 2pt off 2pt on 2pt off 1000pt] \SG;
  \draw[thick] \LG;
  \draw[densely dotted] \QCO;
  \draw[densely dotted] \QCT;
    
  % POINTS
  \fill (QCP) circle (4pt);
  
  % LABELS
  \node at (1.0,5.1) {\footnotesize $T^*_K$};
  \node at (2.3,1.0) {\footnotesize Heavy Fermi liquid};
  \node at (9.0,1.0) {\footnotesize Anti-ferromagnetic};
  \node at (6.0,6.0) {\footnotesize Quantum critical};

  % AXES
  \draw[thick] (O) rectangle (NE);
  \node[left=3pt,above,rotate=90] at (0,4.5) {Temperature $\longrightarrow$};
  \node[below=3pt] at (6,0) {Control parameter $\longrightarrow$};
\end{tikzpicture}