Scott Aaronson

This paper introduces a new technique for removing existential quantifiers

over quantum states. Using this technique, we show that there is no way

to pack an exponential number of bits into a polynomial-size quantum

state, in such a way that the value of any one of those bits ...
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Lance Fortnow, Rahul Santhanam

We survey time hierarchies, with an emphasis on recent attempts to prove hierarchies for semantic classes.

more >>>Olaf Beyersdorff, Johannes Köbler, Sebastian Müller

Motivated by strong Karp-Lipton collapse results in bounded arithmetic, Cook and Krajicek have recently introduced the notion of propositional proof systems with advice.

In this paper we investigate the following question: Do there exist polynomially bounded proof systems with advice for arbitrary languages?

Depending on the complexity of the ...
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Harry Buhrman, Lance Fortnow, Rahul Santhanam

We show several unconditional lower bounds for exponential time classes

against polynomial time classes with advice, including:

\begin{enumerate}

\item For any constant $c$, $\NEXP \not \subseteq \P^{\NP[n^c]}/n^c$

\item For any constant $c$, $\MAEXP \not \subseteq \MA/n^c$

\item $\BPEXP \not \subseteq \BPP/n^{o(1)}$

\end{enumerate}

It was previously unknown even whether $\NEXP \subseteq ... more >>>

Olaf Beyersdorff, Johannes Köbler, Sebastian Müller

One of the starting points of propositional proof complexity is the seminal paper by Cook and Reckhow (JSL 79), where they defined

propositional proof systems as poly-time computable functions which have all propositional tautologies as their range. Motivated by provability consequences in bounded arithmetic, Cook and Krajicek (JSL 07) have ...
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Scott Aaronson, Andrew Drucker

We prove the following surprising result: given any quantum state rho on n qubits, there exists a local Hamiltonian H on poly(n) qubits (e.g., a sum of two-qubit interactions), such that any ground state of H can be used to simulate rho on all quantum circuits of fixed polynomial size. ... more >>>

Lance Fortnow, Rahul Santhanam

We strengthen the non-deterministic time hierarchy theorem of

\cite{Cook72, Seiferas-Fischer-Meyer78, Zak83} to show that the lower bound

holds against sublinear advice. More formally, we show that for any constants

$c$ and $d$ such that $1 \leq c < d$, there is a language in $\NTIME(n^d)$

which is not in $\NTIME(n^c)/n^{1/d}$. ...
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