Looking at another 4K monitor in the Apple Store (http://store.apple.com/us/product/HD971LL/A/sharp-32-pn-k321...), doesn't look like it:

"Note that 4K DisplayPort operation is only compatible with the new Mac Pro (Late 2013). 4K HDMI operation is compatible with MacBook Pro (Late 2013) and the new Mac Pro (Late 2013). HDMI input is not available in the European-market Sharp PN-K321."