There are two koranic verses confirming martyrs are living:
1- Do not say: “they are deed!“ About anyone who is killed for God’s sake. Rather they are living, seven though you do not notice it (2:154)
Some believe that this verse has a figurative sense meaning those who are killed for God’s sake, are not really living but their memory is alive! But it is absolutely wrong because as it is mentioned in the verse they are but we do not notice it.
2- Do not reckon those who are killed for God’s sake are dead, but rather [they are] living, they will be provided for by their Lord , so happy will they be will whatever God had given them out of his bounty, and rejoicing for those they left behind who have not yet overtaken them.
No fear will fall on them nor will they be saddened (3:169-170)
It is inferred from this verse that martyrs (those who are killed for God’s sake) are living after death and they are not dead, but we do not notice it.