NVIDIA has shared the future roadmap for its Tegra SoC at the GTC 2013 event. According to NVIDIA, the company will be releasing Logan and Parker after Tegra 4 processor in the year 2014 and 2015 respectively.
NVIDIA revealed that Logan will be NVIDIA’s first SoC with CUDA inside, thanks to Kepler architecture GPU capable of CUDA 5.0 and OpenGL 4.3. Logan powered devices will go in production in early 2014. With Kepler inside, Logan (Tegra 5?) will be a significant upgrade in terms graphic power over Tegra 4.
Logan will be followed by Parker; it will come with 64 bit capabilities and codename Maxwell GPU. The SoC will go with production in 2015.
You can more about these and the gory details at Anandtech.