entanglement in small self-contained quantum fridges nicolas brunner, ralph silva, paul skrzypczyk,...
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ENTANGLEMENT IN SMALL SELF-CONTAINED QUANTUM FRIDGES
NICOLAS BRUNNER, RALPH SILVA,
PAUL SKRZYPCZYK, MARCUS HUBER
NOAH LINDEN & SANDU POPESCU
SINGAPORE AUG 2013
THE MODEL
FREE HAMILTONIAN
INTERACTION
THERMALISATION
RESET QUBIT TO THERMAL STATE
WITH
WEAK COUPLING REGIME
SOLVING THE MODEL
MASTER EQUATION
STEADY STATE
DISSIPATOR (LINDBLAD)
TRACELESS MATRIX
≈ BIAS BETWEEN POPULATIONS OF |010> AND |101>
AROUND CARNOT POINT
STEADY STATE
CARNOT POINT
ALSO TRUE AROUND CARNOT (BALL OF SEP STATES)
TRACELESS MATRIX BIAS
AROUND CARNOT POINT
ENTANGLEMENT IS DETRIMENTAL FOR EFFICIENCY
STEADY STATE
CARNOT POINT
ALSO TRUE AROUND CARNOT (BALL OF SEP STATES)
TRACELESS MATRIX BIAS
ENTANGLEMENT?
STEADY STATE
ENTANGLEMENT WITNESSES
WHERE
MEASURE OF ENTANGLEMENT
GUHNE & SEEVINCK NJP 2010, HUBER et al. PRL 2010
ENTANGLEMENT ZOO
1. ENTANGLEMENT BETWEEN ANY BIPARTITION
2. GENUINE TRIPARTITE ENTANGLEMENT
DOES THIS ENTANGLEMENT PLAY ANY ROLE?
COOLING
CONSIDER A GIVEN OBJECT (QUBIT) TO BE COOLED
CONSIDER GIVEN RESSOURCES: HOT BATH (TH) COLD BATH (TR)
FIX: ENERGY, BATH (TEMPERATURE TC, COUPLING p1)
COOLING
CONSIDER A GIVEN OBJECT (QUBIT) TO BE COOLED
FIX: ENERGY, BATH (TEMPERATURE TC, COUPLING p1)
CONSIDER GIVEN RESSOURCES: HOT BATH (TH) COLD BATH (TR)
1. OPTIMIZE COOLING TS (LOWEST T FOR QUBIT)
FREE PARAMETERS: E2 and g, p2, p3 << Ei
COOLING
CONSIDER A GIVEN OBJECT (QUBIT) TO BE COOLED
CONSIDER GIVEN RESSOURCES: HOT BATH (TH) COLD BATH (TR)
1. OPTIMIZE COOLING TS (LOWEST T FOR QUBIT)
2. OPTIMIZE COOLING IMPOSING SEPARABILITY TS*
FREE PARAMETERS: E2 and g, p2, p3 << Ei
FIX: ENERGY, BATH (TEMPERATURE TC, COUPLING p1)
COOLING ENHANCEMENT
MONOTONOUS RELATION BTW COOLING ENHANCEMENT AND ENTANGLEMENT (CONCURRENCE)
FUNCTIONAL RELATIONSHIP?
OPEN QUESTIONS
• BEYOND WEAK COUPLING REGIME
• OTHER MODELS
• MACROSCOPIC FRIDGES
• HEAT ENGINES
• QUANTUM EFFECTS IN BATHS