String Dual to Free <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mi mathvariant="script">N</mml:mi><mml:mo>=</mml:mo><mml:mn>4</mml:mn></mml:math> Supersymmetric Yang-Mills Theory

We propose a worldsheet description for the ${\rm AdS}_5\times {\rm S}^5$ string theory dual to large $N$, free ${\cal N}=4$ super Yang-Mills in four dimensions. The is natural generalisation of recently investigated tensionless on AdS}_3\times S}^3\times \mathbb{T}^4$. As case AdS}_3$ it has field description, with spectrally flowed sectors, and closely related an (ambi-)twistor theory. Here, however, we view as critical $N=4$ (closed) background. argue that corresponding gauge constraints reduce degrees freedom finite number oscillators (string bits) each sector. Imposing set residual this reduced oscillator Fock space then determines physical spectrum Quite remarkably, find compelling evidence prescription reproduces precisely entire planar - single trace operators