RT Journal Article T1 Quantum-information engines with many-body states attaining optimal extractable work with quantum control A1 Díaz de la Cruz, J.M. A1 Martín-Delgado Alcántara, Miguel Ángel AB We introduce quantum information engines that extract work from quantum states and a single thermal reservoir. They may operate under three general conditions—(1) unitarily steered evolution (US), driven by a restricted set of available Hamiltonians; (2) irreversible thermalization (IT), and (3) isothermal relaxation (IR)—and hence are called USITIR machines. They include novel engines without traditional feedback control mechanisms, as well as versions which also include them. Explicit constructions of USITIR engines are presented for oneand two-qubit states and their maximum extractable work is computed, which is optimal. Optimality is achieved when the notions of controllable thermalizability and density matrix controllability are fulfilled. Then many-body extensions of USITIR engines are also analyzed and conditions for optimal work extraction are identified. When they are not met, we measure their lack of optimality by means of newly defined uncontrollable entropies, which are explicitly computed for some selected examples. This includes cases of distinguishable and indistinguishable particles. PB American Physical Society SN 1050-2947 YR 2014 FD 2014-03-19 LK https://hdl.handle.net/20.500.14352/35602 UL https://hdl.handle.net/20.500.14352/35602 LA eng NO © 2014 American Physical Society. We acknowledge Spanish MICINN Grants No. FIS2009- 10061 and No. FIS2012-33152, CAM research consortium QUITEMAD S2009-ESP-1594, European Commission PICC: FP7 2007-2013, Grant No. 249958, and UCM-BS Grant No. GICC-910758. NO Unión Europea. FP7 NO Ministerio de Ciencia e Innovación (MICINN) NO Comunidad de Madrid NO Universidad Complutense de Madrid/Banco de Santander DS Docta Complutense RD 18 mar 2026