\documentclass{standalone}
\input{palette}
\usepackage{pgfplots}
\pgfplotsset{compat=default}
% With this compatability setting, pgfplots runs in backwards compatability mode using pgfplots version pre-1.3. It's safe to use a more current version, but axis and tick labels may move and need to be repositioned.

%\usepackage{txfonts}
%\usepackage[mathscr]{euscript}
% The above font packages were used to generate figures for the article, but are here commented out to ensure better compability.

\usetikzlibrary{pgfplots.groupplots}

\newcommand{\mytick}[2]{\draw[thick,#2] (#1, 0.01) -- (#1, -0.15);}

\begin{document}
\begin{tikzpicture}
\def\xclas{1.4966}
\begin{groupplot}[
    group style={
        group name=my plots,
        group size=1 by 1,
        xlabels at=edge bottom,
        xticklabels at=edge bottom,
        vertical sep=0pt
    },
    width=0.8\columnwidth,
    height=0.5\columnwidth,
    xlabel=$\Delta$,
    xmin=0,
    xmax=1,
    ymin=0,
    ymax=6,
    xticklabel style = {/pgf/number format/fixed, /pgf/number format/zerofill, /pgf/number format/precision=1},
    xtick = {0.0, 0.2, 0.4, ..., 2.2},
    yticklabel style = {/pgf/number format/fixed, /pgf/number format/zerofill, /pgf/number format/precision=0},
    tickpos=left,
    ytick align=inside,
    xtick align=outside,
    ylabel style = {yshift=-0.6cm} % <--- this is yshift which makes no sense!
]


\nextgroupplot[ylabel=$f_\mathcal{Q}$, ytick = {0, 1, ..., 6},legend style = {anchor = south east,at={(axis description cs: 1, 0)}},
legend cell align={left} ]
\addplot[virmiddle, mark=*, solid, mark options={solid}] table [x=<Delta>, y=<QFI>, col sep=space, y expr = \thisrowno{1}] {EntanglementData/QFI_vs_Delta.dat};
\addplot[virdark, mark=o, dashed, mark options={solid}] table [x=<Delta>, y=<QFI>, col sep=space, y expr = \thisrowno{2}] {EntanglementData/QFI_vs_Delta.dat};
\addplot [domain=0.0:3.5, black, dashed]{3 };
\legend{\textcolor{virmiddle}{With polarization factor},\textcolor{virdark}{Without polarization factor}};

\end{groupplot}
\end{tikzpicture}

\end{document}


