dorsal/arxiv
View SchemaQuantum Information and the PCP Theorem
| Authors | Ran Raz |
|---|---|
| Categories | |
| ArXiv ID | quant-ph/0504075 |
| URL | https://arxiv.org/abs/quant-ph/0504075 |
Abstract
We show how to encode $2^n$ (classical) bits $a_1,...,a_{2^n}$ by a single quantum state $|\Psi>$ of size O(n) qubits, such that: for any constant $k$ and any $i_1,...,i_k \in \{1,...,2^n\}$, the values of the bits $a_{i_1},...,a_{i_k}$ can be retrieved from $|\Psi>$ by a one-round Arthur-Merlin interactive protocol of size polynomial in $n$. This shows how to go around Holevo-Nayak's Theorem, using Arthur-Merlin proofs. We use the new representation to prove the following results: 1) Interactive proofs with quantum advice: We show that the class $QIP/qpoly$ contains ALL languages. That is, for any language $L$ (even non-recursive), the membership $x \in L$ (for $x$ of length $n$) can be proved by a polynomial-size quantum interactive proof, where the verifier is a polynomial-size quantum circuit with working space initiated with some quantum state $|\Psi_{L,n} >$ (depending only on $L$ and $n$). Moreover, the interactive proof that we give is of only one round, and the messages communicated are classical. 2) PCP with only one query: We show that the membership $x \in SAT$ (for $x$ of length $n$) can be proved by a logarithmic-size quantum state $|\Psi >$, together with a polynomial-size classical proof consisting of blocks of length $polylog(n)$ bits each, such that after measuring the state $|\Psi >$ the verifier only needs to read {\bf one} block of the classical proof. While the first result is a straight forward consequence of the new representation, the second requires an additional machinery of quantum low-degree-test that may be interesting in its own right.
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"abstract": "We show how to encode $2^n$ (classical) bits $a_1,...,a_{2^n}$ by a single\nquantum state $|\\Psi\u003e$ of size O(n) qubits, such that: for any constant $k$ and\nany $i_1,...,i_k \\in \\{1,...,2^n\\}$, the values of the bits\n$a_{i_1},...,a_{i_k}$ can be retrieved from $|\\Psi\u003e$ by a one-round\nArthur-Merlin interactive protocol of size polynomial in $n$. This shows how to\ngo around Holevo-Nayak\u0027s Theorem, using Arthur-Merlin proofs.\n We use the new representation to prove the following results:\n 1) Interactive proofs with quantum advice: We show that the class $QIP/qpoly$\ncontains ALL languages. That is, for any language $L$ (even non-recursive), the\nmembership $x \\in L$ (for $x$ of length $n$) can be proved by a polynomial-size\nquantum interactive proof, where the verifier is a polynomial-size quantum\ncircuit with working space initiated with some quantum state $|\\Psi_{L,n} \u003e$\n(depending only on $L$ and $n$). Moreover, the interactive proof that we give\nis of only one round, and the messages communicated are classical.\n 2) PCP with only one query: We show that the membership $x \\in SAT$ (for $x$\nof length $n$) can be proved by a logarithmic-size quantum state $|\\Psi \u003e$,\ntogether with a polynomial-size classical proof consisting of blocks of length\n$polylog(n)$ bits each, such that after measuring the state $|\\Psi \u003e$ the\nverifier only needs to read {\\bf one} block of the classical proof.\n While the first result is a straight forward consequence of the new\nrepresentation, the second requires an additional machinery of quantum\nlow-degree-test that may be interesting in its own right.",
"arxiv_id": "quant-ph/0504075",
"authors": [
"Ran Raz"
],
"categories": [
"quant-ph"
],
"title": "Quantum Information and the PCP Theorem",
"url": "https://arxiv.org/abs/quant-ph/0504075"
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