Perplexity AI用什么模型，这是Perplexity AI自己搜索给的结果：
Based on the search results, Perplexity AI uses the following AI models:
Perplexity's free version uses a model based on OpenAI's GPT-3.5 combined with Perplexity's own large language model (LLM) that incorporates natural language processing (NLP) capabilities.

Perplexity's paid "Pro" version provides access to more advanced AI models, including GPT-4, Claude 3, Mistral Large, and an Experimental Perplexity Model.

The search results indicate that Perplexity AI was founded in August 2022 by Aravind Srinivas, Denis Yarats, Johnny Ho, and others.
Srinivas previously worked at OpenAI and now serves as Perplexity's CEO.

同样问秘塔AI，秘塔AI用什么AI模型：
秘塔AI搜索采用的MetaLLM模型由秘塔科技于2022年全栈自研。该模型于2023年通过《生成式大模型备案》（第二批）、《大模型算法备案》（第二批）。
目前秘塔AI搜索尚处于0.99版研发测试阶段，我们深知当前模型及产品效果还存在诸多可提升空间，还希望大家给我们多一些耐心，让我们在有限资源之下持续提升产品。